Yep! People will buy WoW tokens from the auction house with gold, and they can either redeem the tokens for $15 of shop balance or 30 days of game time. I like making gold in game, so anything I've bought from Blizzard over the last few years (including WoW expansions and other games) has been with gold.
The price of tokens went up by about 100,000 gold after this mount got announced and they were selling out fairly regularly for the rest of the day. It seems to have stabilized now, though.
Yes, people pay $20 to buy a WoW token from the cash shop which then gets sold on the in game auction house. That person gets in game gold (the amount fluctuates), and the person who bought the token from the auction house gets their choice of either $15 of shop balance or 30 days of game time.