Every business needs an online presence, especially restaurants.
Having your own platform is valuable
Yes, there are lots of other places online where you can establish your business such as Facebook, Yelp, and Google Places. A number of paid platform also exist such as menu hosting service SinglePlatform and the plethora of food deliver apps. These are all well and good, and you can't use all of them efficiently. Pick and choose what you think could help your business, but they are not a substitute for your own website.
You need a place to build landing pages
Digital marketers drive traffic from advertising campaigns to a "landing page", which is highly targeted to the specific campaign they are running. Each ad group on Facebook, for example, would get its own landing page that is tailored to that ad set. Marketers create tons of landing pages.
You can use landing pages to promote different aspects of your business, and having your own website enables you to do that. For example, you might have a landing page about hosting events at your venue - many clubs and organizations are always looking for locations to hold private events. Maybe you would want a landing page for your drink specials or weekly food deals. The possibilities are endless.
Landing pages rank in Google search and will bring in traffic to your website, and that will bring in more business. You could also run paid ads on google for 'private event venue in _your town_'. This is a great way to boost revenue.
SEO & Content Creation
Having your own website gives you the ability to create lots of pages, including landing pages discussed above, that rank in google and drive revenue for you restaurant. A Facebook page, while still worthwhile, is more limited. It's just one page with a list of posts, and it's not going to rank in the same way your website will. Facebook pages are overhyped in my opinion, and I rarely ever go to a business's Facebook page. However, I find myself on their websites all the time!
Restaurants are uniquely positioned to benefit from having a website because local search results are easy to rank. For example, if someone searches "food specials on Saturday in such and such a town" your restaurant can show up, assuming you have a page about that. Why is SEO easier for local search terms? They are lower competition - meaning there are only a limited number of restaurants in your town that are relevant. Compare that with a search term like "leather boots" - it would be almost impossible to rank for this word because there are so many matches for "leather boots". I hope that makes sense, and to sum it up: building out your restaurant website is very much worth doing, and it will pay off in the long term. As your websites begin to rank in Google search, it will bring in new customers for free!
How do I build a restaurant website without wasting lots of money?
It's so easy to waste money when building a website, especially when you're not a techie and don't understand how websites are built. And they are built in many different ways, using many different technologies. Consulting companies that build websites for local businesses are notorious for taking advantage of their clients lack of knowledge. With a little bit of education, you can avoid paying exorbitant fees every month for upkeep and maintenance on a website that is supposed to help your business and not bleed cash.
Avoid WordPress at all costs - trust me I'm a developer
Companies that build websites (consulting companies) target restaurant owners and tell them that they need a website, and it needs to be done in Wordpress because that's what everyone else is using. As a web developer that has worked with Wordpress, I can tell you 100% that the platform is a disaster and a money pit. The cost for maintenance and customization can run in the tens of thousands. But this is the bread and butter of consulting companies, and they make their money by charging monthly retainers to host and manage your wordpress site. The 'retainer' fee is high and you pay whether they any do any actual work or not - they usually give you maybe 5 hours of development time per month (as if that's a lot). If you are a small restaurant, you don't want to do this - trust me.
Why is Wordpress a horrible restaurant hosting platform? It's a bad platform for everything. It requires lots of development work to get something that looks decent unless you want an off-the-shelf template and only plan to publish simple blog posts. The interface is clunky and hard to work with. Any kind of custom work is a hack job. The platform itself relies on thousands of 'plugins' to do mundane things. These plugins are made by independent developers, and they are constantly getting out of date. To you them, you have to set them up yourself. Sometimes they stop working altogether. If you're paying someone to manage all this for you, costs add up fast.
Just use Squarespace
I've recommended SquareSpace in the past to people considering other options i.e. Wordpress. SquareSpace has dedicated templates for restaurants, and this is a large portion of their business. They know what you want in a restaurant website better than you do. It requires no coding / development work, no separate hosting account, and no exorbitant consulting fees. The average person can use the drag and drop feature to quickly build a beautiful website that will do everything you need. Their customer service is also top notch. SquareSpace Menu Blocks
SquareSpace has a feature called Menu Blocks
that allows you to create you menu without having to upload .pdfs (lots of restaurants upload .pdf files of their menu, and they are hard to read on mobile devices (usually have to be downloaded) and search engines can't index them.). SquareSpace's menu blocks solution is easy to set up and is SEO friendly (google can index your menu items because they are part of your website - this means your website can show up when people search for items on your menu).
Squarespace also comes with lots of additional features such as ecommerce, contact forms, etc. With Wordpress, you would have to add all these things manually through plugins - a messy and time consuming task.Bottom Line
SquareSpace really has it together, and their service is a lifesaver for 95% of restaurant owners. They understand that you have enough to worry about - let them handle the development work.
Wix has tons of features for restaurants
Wix is another excellent choice for building your restaurant website, and their service is loaded with features that are often provided by 3rd parties that charge hefty commission fees including:
Online Ordering - Yes, Wix's restaurant website builder allows you to take online orders. Pay no fees or commissions to 3rd party apps.
Table Reservations - No longer will you have to rely on apps and services like Open Table - your Wix hosted website can do it all!
Menu Builder - Create your menu with Wix's dedicated tool - no more uploading .pdfs or image snapshots of paper menus. Search engines will love it.
Most restaurant owners do not realize what powerful features they can have on their own website through Wix and SquareSpace. These companies have been quietly building features for years. All the press goes to the hottest new food deliver app or reservations scheduling service, but you can have those features for a reasonable price.
Avoid addon services
It may be tempting to build your restaurant website through a service you may already be using such as ChowNow. They have an 'add on' feature that is basically website template for you to use. While I cannot speak for their service specifically, it's common practice for vendors to get you into their 'ecosystem' where they can market one thing after another. They bundle them and you often wind up paying for a bunch of 'fluff' that you don't use.
Check out PopMenu
PopMenu is its own animal - they are a startup based out of Atlanta GA. They sell a 'customer engagement' solution, and you get your own website that has tons of social media like features built into it. The idea is that customers can go to you PopMenu website, place an order, pick it up or have it delivered, and they get prompted to leave reviews for the specific dish they ordered. This is different from Yelp, for example, where you leave reviews for the restaurant itself - not any one dish.
They have a graphic on their website that does a much better job of explaining it than me, but you get the idea. Does it work? Is it worth the price? It's an interesting concept - without having been to a restaurant that uses it and left a review, I cannot provide an informed critique of their product. I suspect it would be hard to measure ROI, and I would want to see the conversion rate - what percentage of customers actually interact with the service by leaving a review or commenting. Then I would want to know how much their services has increased revenues at participating restaurants. They should be able to tell this if does in fact make any impact on the business.
Make sure to do your research and ask questions - the last thing you want is to pay a bunch of money and invest lots of time without knowing if it's helping.
If you're reading this, it is likely you don't already have a website or maybe you haven't even started your restaurant yet. My advice to you is to start small. Don't go spending lots of money on a fancy website with lots of features until you get a successful business going. Having online ordering and a fancy menu is nice, but those features won't help you acquire customers. They will make things easier for your current customers. Focus on growing you business and start with a basic website. When things progress, start testing by adding new features.