Because the boss can feel better about underpaying his employees if he rationalizes it by saying they get tips to compensate the inadequate salary. And of cour

Because the boss can feel better about underpaying his employees if he rationalizes it by saying they get tips to compensate the inadequate salary. And of course, all the bottom-feeders in the PoS and credit card processing industry which also stand to gain as they can sell the tipping prompt as an extra feature.