While I can understand the psychology of putting the 20% first, I will never leave a tip for any service unless it is in the United States and I know the waitst

While I can understand the psychology of putting the 20% first, I will never leave a tip for any service unless it is in the United States and I know the waitstaff is making 2$ an hour and their wages actually come from tips. But any sort of touch-screen tipping is simply companies begging for more money from you. And if tipping is considered as revenue, then I think it is a deceptive practice. Why not just raise prices instead of have some random process (will a person tip or not?) dictate your revenue? it all seems like convolutions to increase the entropy of the consumer decision making to trick them out of their money.