Yup, and accessing table availability requires integrating with the restaurant's point of sale system so you can track when tables are getting seated and cleared.
Innovating technology wise in the restaurant space is pretty tough cause sooner or later you're going to hit the wall of having to integrate with a dozen or more point of sale providers, no matter what you're trying to do (mobile/online ordering, reservation/waitlist systems, reporting systems, etc).
Oh, and because of their incredibly low profit margins, most restaurants can't afford to buy this type of tech. And the ones that do typically keep it for 5+ years between upgrades.