I never understood the "less social interaction" argument. Cashiers don't care if you go through the whole interaction with them without making eye contact and only saying what's absolutely necessary for the transaction. Plus, self checkouts are very picky and if you mess anything up even a little bit they start loudly inviting someone to come help you anyway.
A human at the other end of the exchange forces you to think about that human, to consider that human, and to acknowledge the existence of that human, whether they speak or not. Don't have to feel that way with a machine.
Yes, some people are that bad that even silent interaction produces anxiety. It's why I prefer emails and texts instead of live phone calls. I can communicate on my own time after thinking it through and not feel obligated to respond immediately (that's what Asperger's does to a MF)
Lol I'm autistic and like a 10/10 on the MBTI introversion scale.
I just preferred the interaction with an employee who wears a large button saying "I really wish I weren't here right now" compared to using a machine which would loudly announce that you're an idiot if you don't follow its instructions precisely.
I would rather spend (modestly) more time checking my own than less time standing idly with nothing to do but watch some kid checking out my goods. It feels better to be an active participant. Where it breaks down for me and my 12 items is when all the self-check lanes are clogged with people trying to ring up a full cart of groceries, who still haven't figured out how to work self-checks, who are encumbered by a baby in one arm and a phone in the other hand, or who just can't move all that well.
Managers using the presence of self-check as an excuse to understaff the actual checkouts makes all of those problems worse, and makes the checkout process suck for everyone.