So I've noticed ChaosPringle in his world record changes the time of his switch at the beginning and I've seen other runs do this, so why are people doing it and what purpose does it have

Edit : Also a lot of runners now have a -10 start instead of starting when pressing Start does this have to do with the timer change or is it for convenience or some other reason

It's for a trick in sand kingdom with the seed

N U T

It's a Daylight savings time exploit to get the seed on Sand Kingdom to instantly grow. Nicroveda made a video explaining it in the video here