Around here there are a variety of supermarket solutions. Morrisson’s for example near me has about a dozen cashier lines, usually 3 or so open unless there’s a rush. They have a self-checkout section like people are describing, with the small bagging area (about big enough to cage a toddler), maybe 10 of these. They also have a trolley self-checkout area, which is the same but has a bagging area big enough to cage a lioness.

M&S have cashiers, basket self-checkout, and a third scan-as-you-shop section, where you put things in your basket and scan them, and on your way out you put the scanner back and tap your phone and bag stuff, or if you’re using a trolley, just push it out to your car, whatever.