This does mean you block the person behind you for much longer, but that's the store's problem not mine.

If it means there's never an "unexpected item in bagging area" it probably overall reduces time.

I do this too, but most stores have plastic bag holders on the scale that clutter things put and make it harder to stack items before bagging.

I imagine its regional, but where I'm at those are long gone. Now you gotta bring your own bags or pay for each of the ultra flimsy 'reusable' store brand bags.