P2P isn't any more convenient than the half-dozen music stores that already exist. It's a halfway convenient source for movies and television--but the former you have extant mail-order services, and for the latter you can just build a box and record the darn shows yourself.
It's very convenient for sharing documents, legal media, free software, etc. Should such a medium be outlawed because pirates like to use it too? Shall we also outlaw FTP, or TCP/IP?