Not sure it's faster. I worked as a cashier for awhile at a grocery store. A 2 person team, one scanning/keying in items and one bagging, is a ton faster then you doing it all yourself. Customers who would do this were great. The worst ones were the ones who just sorta stared at you as you rang up then bagged their groceries for them while complaining about long lines.

The other big speed enhancement is memorization of common PLUs. Seeing bananas and just knowing the code (4011 or 94011 for non organic/ organic respectively) Is a lot faster than trying to navigate through the menus. It's on the label but most people don't seem to realize that.

That said I still think it should be self check out all the way, letting one person run 6 self checkouts at midnight so I don't get caught behind the person buying two shopping carts of misc stuff while I'm just trying to grab an orange juice is miserable.