I'll be paying close attention to if this trend catches on. Blizzard is often a trailblazer in features it introduces (example: Exclamation Mark = New Quest, Question Mark = Completed Quest; Talent Trees).
Here is what I wish Blizzard would do with WoW. Instead of paying $15 a month for game playing time, they should sell you game items that represent a week of play time, so let's say $15 buys you a stack of 4 in game chips. The player can then activate those chips to extend their play time or they can trade them with other players or sell them on the auction house for in game gold. On the other end, blizzard can enable a program to buy back chips at say 70% of the original value. This gives people a legitimate avenue to "buy" items if they want, while also controlling the gold/item farming community.