To the OP, no you obviously don't need to read music to be in a band.
I can't read a note but I have to admit that it's lost me some gigs, mainly cruise jobs.
It took me a fair while to learn our set, so it would have been useful to read music and have a written score to work from. But saying that, it improved my ear training no end. Our brass players are rteally the only musicians that follow a score, and I sometimes envy them being able to sit in with any musical situation at short notice.
I think it's more important to develop a good sense of time and groove. The best reader in the world won't get the job if he or she doesn't possess those qualities.