This seems more like a regional thing these days, over here. I haven't seen grociers bagging groceries for customers since I was a child. I mean... outside of delivery or curbside pick-up. I do remember it being a pretty standard thing, though. Heck, it used to be a dedicated job position.

The bagger is presented as a courtesy, someone to do the work for you. In reality you're exactly right: it's to keep a brisk pace for the transaction. And if it takes too long to finish the transaction the manager can also yell at someone to speed it up.

We have Aldi here (at least in some of the states) so some of us know what you mean. But it's definitely not the norm, so many customers aren't very acclimated to the rapid baggerless checkout.

Hear hear! Why is this so hard to understand in this damn country?! (US)

Some popular supermarkets will have grocery baggers here in Norway on super busy days before long holidays, for efficiency to keep the lines moving. Maybe two or three days a year.

Same in the UK, they scan it, then you're on your own.