I have one. Don't use it. Probably doesn't even help to be honest. Med schools are not going to go looking at every applicant's online accounts. If they have concerns, they may look, but idk how often they look just because they want to (as a whole ADCOM, perhaps some members look > other members)
as far as if it will be beneficial to your career once you are graduated? i dunno, but probably not hugely significant