It's not. It's a surrender to Apple (AAPL).
The Facebook credit scheme, which started on its 'ville games and moved to its advertisers, worked fine on PCs, where Facebook dictated the environment. On the iPhone, which remains the only fully-monetized mobile platform out there, not so much.
Facebook couldn't bridge the gap between its funny-money and real cash, between its adolescent fan base and the real world, because Apple was standing in the way with its 30% toll bridge. Publishers have learned to navigate this bridge, and by blowing up its own currency Facebook lets them do so in safety through its apps.
The funniest comment came from Plink, a start-up which was to be based on Facebook credits, which claimed this increases their market. It doesn't. It kills their market. Not just Plink, but hundreds of other entrepreneurs who were gearing up to turn credits that kids earned for doing stuff into valuable prizes and political contributions.
Facebook stock has spent the last week recovering, building a base in the $30/share range, as the clock ticks on lock-up periods for shares held by employees and other insiders. It may have just weeks to get real sales through Facebook apps, and prove itself as a channel, before investors face a flood of new shares and start demanding real profits, not just credits and audience share.
I think the stock can be manipulated through the end of the lock-up period. I don't think it can stand past that. Feel free to disagree.