Josh Constine at TechCrunch:
Facebook will then automatically upload photos you shoot to an unpublished album only you can see. From there you can authorize which photos you want posted. More details on enabling and disabling Photo Sync can be found in the Facebook Help Center, which we discovered now notes the feature’s presence on iOS. By default Facebook tries to upload photos immediately, but you can configure it to avoid burning your data plan.
If you think that ease-of-use is the motivating factor here, I’ve got an invisible something-or-other to sell you. Facebook wants your data. They always have, and they always will.