The question is really why ArenaNet does that. Maybe they need the money they earn with the auction house to keep the game and the development running (yes of course). And because so little comes in, they are forced to rely on such systems?
So if I knew that ArenaNet needs the money urgently, then I would spend a few euros a month for it and buy something in the AH. But this development of the game without transparency why this is done so I can not be bothered.