@risingphoenix@Impossible_PhD up to a certain degree this is useful because it helps people to notice that there is a 1-2 metric ton box rolling towards/past them.
in the early days of the reemergence of electric cars there were a few accidents because people walked in front of slow moving ones as they did not hear the cars at all and just walked over a street.
so almost everywhere governments implemented laws that they have to make some sound that makes it recognizable as a car.