Interesting project .
In my country there are some cafes which accept bitcoin, but not in such a fancy way - just a POS. Sometimes transactions time is longer than paying with fiat/mc/vc. How are  you going to deal with this issue?

And another question - a rethorical one: if most visitors will pay with crypto, is there any way for restaurant to use this profit in crypto to pay taxes or order needful supplies? I think it can be worth if you think about it  and offer convenient ways of spending money in crypto to cover restaurants' needs. Maybe build any partner relations with related retailers offering them to install your terminal.  Just an idea.

Otherways, good luck