It's like you have never been in a coffee shop. A coffee shop needs good vibes, a good coffee supplier, and a cash register. It doesn't even need an espresso machine. The best coffee shop in Oslo only uses aeropress. But it also needs baristas who like coffee and appreciate the chemistry of it.
You seem to have created the anti-human coffee shop.
You don't need my number to sell me coffee. Asking for it is an invasion of my privacy. If you insist on an awards program of some kind, it already exists in it's ultimate form, the stamp card.
Customers should not be tasked with evaluating employees. They have no expertise in the matter.
Employees should not have wages effectively stolen from them under the auspices that "good work is rewarded". You know how you reward good work? Raises, profit sharing, more responsibility, benefits programs, you know typical things employers do for employees in a worker centered environment.
All this also assumes anyone uses these systems as intended. I doubt customers will select ratings in any meaningful way and you will have no way to ground truth if they do or not. Nobody will ever care enough to sit through customer interviews to evaluate whether your one question survey is valid or not. Certainly not for a cup of coffee.