iPhone Backup vs iTune Media location?

Hi,

I've just noticed that in addition to the folder I've chosen for my iTunes backup (E://iTunes), there is also a huge 11GB folder on C drive (C:\Users\ACER\AppData\Roaming\Apple Computer\MobileSync\Backup).

I realize that that the latter is the real iPhone backup, including contacts, settings, and everything else, but at that size it must also include all of my apps and music. This seems partly redundant, and my iTunes already backs those up to the folder on E Drive. And from what I read, this C drive location is not really movable (officially).

Why does iTunes/iPhone need to store those large app files in 2 locations? Any way to get rid of one?

Thanks