At least in the cafes I worked in as an undergrad we split tips between the waitstaff and kitchen, which of course also sort of shifts around the "rewarding good service" aspect, but I think then you feel like you're letting down your coworkers if you piss off customers enough for them to tip badly.
Why does it matter? That isn't some kind of gotcha.
I wouldn't mind if 100% of customer facing jobs were tipped. At worst, is an optional lower price to pay if you are dissatisfied or light on cash. Normally it is just I'm part of the price. I'm not sure why people would be so much happier paying 120% the price instead of 100% and then a 20% tip. It's all the same in the end
Part of the problem is that an expectation of tipping is cropping up in many places where it didn't exist before, and prices certainly haven't dropped 20% to compensate. In these circumstances I would rather just pay 100% of the price and be done.
I think it's partly a crude fix for the problem of some states allowing for waiters and bartenders specifically to be paid below minimum wage[1], as low as $2.13 per hour in some states! Which is of course far worse than most customer-facing jobs.
What is customer facing? Doctor to patient? Employee to employer? Real estate agent to homeowner? Everyone is selling their labor to someone, and everyone has a customer.
