In fact she wears her leotard for hours after practice and even falls asleep in it. I figure it is less laundry for me to do so I don't complain. I am not sure how wearing a leotard to bed is comfortable though.
I did that all the time when I was her age. She'll grow out of it, especially when she grows a little and the leos get a little tighter and start leaving big red marks at the elastic.