Chaos Dwarves: illegal

Is it me or are Chaos Dwarves an illegal unsanctioned army? Until there is a book I don't fathom the fascination. Armies like that and ones like Nippon or Amazons just don't fit the standard mold. Much like Squats in Warhammer 40k their time has come and gone. Until GW sees fit to give them the real treatment they will be a fad and illegal list to me.