Café rio and those types don’t need it. I’d rather get my own drink than pay 20%.

My favorite restaurant in DC had a self serve soda machine and no staff, then they changed and put the soda behind a gate and forced you to have a server. I started going less and less. And servers make things take longer not faster; you have to wait for menus and wait for drinks vs just getting it yourself.
At least give people the option