Hiya no they don’t. They really only care about your grades/how you did well at interview if your course requires one. I guess it could be helpful to talk about your leadership experience in the interview or in your personal statement, but universities wouldn’t really mind if you don’t good luck with your application and experience
No. So dont waste you time doing it. Unis want solid grades and a good Personal Statement with academic focus on your chosen subject. 'I'm a Prefect' is totally meaningless.