Easier to take care of.
My mom was 5’3”, and weighed 95 lbs (soaking wet), and she had very short hair because it was so much easier to take care of.
Is 95 heavy? Being 5’10” since I was 12, I have no idea.
Anyway, I know that’s usually the reasoning.
I also got short hair as an adult because of my husband’s preference - but I’m growing it again. In my case, I’m finding short is actually harder for me to make look good. I have too many cow licks that seem worse when it’s short. I love that it washes and dries fast, but otherwise - I spend just as much time fighting it in the mirror as when long.