at least where i live, two-button light switches are called “chandelier switches” because they were originally used to control a single chandelier using two live wires and one neutral. having all the bulbs powered would make the room too hot, so they made a single lamp into two circuits.

also, fun fact, dimmer switches used to be a big file hazard because the current they had to dump from big light fixtures meant they would heat up inside the wall which could make the insulation catch fire.