It would take many cameras working together to pull this off...what happens when you drop out of sight? Feels like a big vending machine...If they're not competing with big grocery stores, then this won't scale well...right?
Really this whole thread is all just rank speculation that'll be mostly confirmed or denied once a store actually opens and people can look around and see what's going on.
Also as for scaling it's a fixed cost to cover a larger area compared with a variable cost if they're using RFID to scan when you pass through the turnstiles so really a camera based system probably scales better than a tag based system.