You must not be old enough to remember the dreaded, hidden seatbelt buzzer that malfunctioned half the time.
Indeed, but maybe you have only old cars that do not require you to press the brake pedal in order to put it in gear or that lock the doors once you do put it in gear.
Technology is vastly improved today but I would guess you know that already.
( I removed that wiring in both my 78 and my 79 Trans am) ;)