I think a girl who marches with a sousaphone, and who plays tuba, is pretty interesting. This is, at least, a good subject for an essay. See http://talk.collegeconfidential.com/parents-forum/1797102-elite-admissions-finding-the-and.html#latest
If she’s not going to be a music major, I don’t think it’s too likely to result in merit aid. But it might help her get into a more selective college, because it’s cool.