Not sure if this was posted here already but LIMIT, one of the top raid progression guilds in the world faction changed from Horde to Alliance, presumably for access to 2 or (possibly) 3 pieces of 400ilvl gear that the Alliance has access to currently based on Warfronts and the Alliance having a smaller population playing Warmode and therefor the Alliance receive a 30% buff to resource gain.
They spent $0 real money themselves and the faction change was funded by selling mythic clears (10-15 million gold to have blizzard credit to purchase the faction change).
This move appears to be temporary, evidenced by the name they chose to rename the guild to: "this game is bad". Yep, that's right.
My own opinion is that the faction change to take advantage of yet another game decision mistake by ActiBlizz is funny. The name of the new guild is really funny (true btw imo). Lastly, someone likely paid real money for the gold via game time token purchases, so in effect, ActiBlizz made money of this which is really, really sad.