I'll keep this short and sweet.
1. Andy's getting old and may retire suddenly due to boredom, injury, or other. Weidman is a real talent, young, and has hopefully gained some draw, and can potentially lead or contend at MW for a while to come.
2. Huge PPV potential if they can make the rematch, which I think they will.
3. Massive uproar. "All publicity is good publicity". While the clowning/KO were shocking, and disappointing to some, to the extent that some are calling it a work, I think the eyeballs and notoriety of this fight will only serve to raise the UFC's profile and draw more interest. I don't think the sport's legitimacy has been threatened enough to reduce its popularity.
4. Opportunity for super fights. I'm not convinced that Andy vs GSP or Jones is automatically scrapped just because he lost. Edgar, Vitor, Chael, Tate - plenty of title shots have been granted to undeserving challengers lately, for whatever reason. Andy remains one of the most deserving of a title shot against Jones, or a superfight at MW or lower catchweight with GSP. In fact, it seems that losing the belt may give him more mental freedom to break out of his "defend the belt, or fight lower tier LHWs to mark time" mold.
Argue with me.