I love self service tills, and my choice of local convenience store is the one which has them, rather than the one which doesn't (both similar size, both smaller franchise chains, one a One-Stop, the other a Spar). Far quicker to use the self service tills, rather than be forced to wait in a queue behind people wanting to chat or taking forever to find their purse, or deciding they want something else and wandering back to the shelves whilst holding everyone up.
Yes, they're hard to use at first, sometimes clunky, but when you get experience in using them, where to put unscanned/scanned items, how to press buttons for weight of fruit/veg, when to present cards, etc., it gets easier and easier the more you use them.
In the store with them, the staff are actually out doing useful things on the shop floor, like stacking shelves, and are more accessible to ask questions rather than being stood behind a counter waiting for Aunt Ethel to find her purse!