This is partially done to compensate for terrible wiring. Lots of people are fond of using small wires and going long distances leading to a lot of voltage drop

This is partially done to compensate for terrible wiring. Lots of people are fond of using small wires and going long distances leading to a lot of voltage drop. They often send 125v or so from the transformer which is 123-124 at the panel, 120 v or so at the receptacle, and >100v after someone decides to run something on a few hundred feet of #18 extension cord.