Re: Hatsune Miku
Twenty - do you not remember Boney-M or Milli Vanilli??
Vocaloid is a good tool for a certain type of angsty teen with budding music talent they might not otherwise discover.
There's been quite a few that have gone on to real music careers (mostly Japanese though, Vocaloid never sounds quite the same in english).
Possibly what gets used more is MMD for music videos.