I started using grocery self-checkouts during COVID, but I’ve kept using them because there’s rarely a line (and I’m a misanthrope). I’d probably go back to using regular human checkouts if I had to dig through all my crap to prove what I bought.
Having said that, I’ve noticed myself making mistakes. I’ve accidentally failed to scan an item, and I’ve accidentally entered incorrect codes for produce. When I notice, I fix them, but I’ve probably missed a few.
I guess the easiest answer is for grocery chains to reinvest some of those windfall profits and hire more cashiers.
I never have a problem bagging my own groceries at the cashier. It’s the best of both worlds: highly skilled checkout operator and a fairly skilled bagger.
I think the dedicated baggers they used to have were better at it than I am, though. They somehow managed to Tetris everything into appropriate bags that were of similar weight and were almost as stable as using a box.
I think the throughput of a cashier and a skilled bagger is much better than a bagging cashier and definitely better than self-checkouts.