Generally, as here in CO, there is still a minimum wage for staff that are regularly tipped, it’s just lower. I believe it’s also (again, as here) generally required that any time the tipping doesn’t make up the difference, companies are required to make it up instead.
That being said, it’s basically a way to advertise much lower prices than they actually charge. Roles that often get tipped tend to make pretty good money, and companies would basically never want to pay that much for those roles (especially when they are used to paying even less than minimum wage).