Why would you and how can you shove your spare cuffs in your two pockets. (Especially when, since you may be using your suit storage AND belt slots, you use a pocket for your internals which leaves you with a single cuff.)
Anyway, since the normal recharger cannot be pushed away like a closet when dragged, nor can it run out of energy, and since you can drag that around with you without encumbering you, you don't really need a backpack that does the same thing in a shittier, inefficient way. The only actual downside is it takes one click to remove it from you, and that's really the only upside of the backpack, that it sticks on your inventory.