IMHO, tipping is a totally irrational way to compensate employees, but at least the places I have lived in the US, it is not disputable: tipped jobs like bartenders, baristas, or restaurants server make significantly more money than untipped jobs doing similar work, like fast food workers.

Does tiping make any sense? Not to me. Does it (strangely) result in higher wages? Yes, and it's not even remotely close (unless there is some argument that being a barista is markedly more skilled than working at McDonald's, an argument I am somewhat skeptical of).