But it's not efficient, is it? These people could be doing something more productive with their time than staffing a checkout in order to make small talk.
Who do you optimize for? IMO, ideally not the company.
I don't know what your experience is, but I always find self-checkout massively more efficient for me and I'd always prefer it and would choose shops that offer it over those that don't.
I can just breeze through with my AirPods still in listening to my podcast, not having to wait for anyone else or have anyone else wait for me, not having to say anything, and just get on with the rest of my day and what I really want to spend my time doing.
It’s lower effort because talking is a bigger cognitive burden for me than scanning a few items. Over time with experience, you get as fast as an employee would be anyway.
I enjoy seeing this group of young people given such a broad responsibility and I acknowledge them and their stellar job. And they acknowledge me.
But who am I, I just enjoy Old Europe.