@yirggzmb People don't like to have things taken away. I barely remember gas station attendants pumping our gas growing up. I don't feel like I'm missing anything, at the gas station, like I am with the checkout service.
I also know some elderly folks ( ☝️ not me, not yet ) who get lonely and that brief interaction with their checker means a lot.
I'm sure you know them; the ones that talk your ear off while your trying to get to your next customer. Sweetly annoying