Where I was living at the time had a very large grocery store, with like 15 checkout lanes, and like 12 self checkout locations. They shut down the self checkout, and had like 4-6 checkout lanes open at all times (24 hours), but they had 1 line that you had to go through before you were allowed to go to a register. So you had to wait until the previous person's groceries were already packed and they were paying. It was super efficient, and made it much easier to get around the store.
I wish it would come back. Well, I also don't live there anymore.