The people that will be playing "for free" will be spending their gold on tokens that other people spent RL cash on (more per month that a subscription), that's the clever bit about it, with the token-sellers thinking they'll get in-game rich and the buyers going "I'm playing for free, suck on that, Blizz!", in the end Blizzard are the winners, selling playtime for €5 a month more than usual. :3