You are correct, as long as all people in the store have set up accounts to be billed.
If someone without an account sneaks in, blends in with the crowd, blends in with the people exiting the store with their full shopping carts, There could be a big shoplifting problem. They are still going to need actual human being employees on the premises to provide at least some minimal level or appearance of security.
I think that if your face is not in the current system taken at the turnstile and cameras cannot link to an account or facial software after seeing you remove an item from the shelf then there is an alarm immediately.