No consumer wants these messages. I understand why restaurants need them and why they are profitable, but actually recipients will be irritated (even though they "opted in").
My concern is that these will turn SMS, one of the last (mostly) clean communication channels, into another cesspit like email and the web have become.
I'm not asking what you're doing to prevent that because you can't build this into a successful company without moving the needle in that direction.
I just want you to question why you're doing this and whether your business is creating a world you actually want to live in. To me and everyone who isn't profiting from it, it's pollution of our personal lives.
(Unrelated: I started a company years ago with restaurants as customers. They are by far the worst people I've ever had as clients, if you could even sell to them. It's basically impossible to build a profitable software business with restaurants as customers -- even "Big Delivery" is unprofitable).