As an autistic person, I certainly prefer self-checkout. I would much rather have to deal with an annoying error than have to interact with a cashier, or worse, having that cashier ask about my day or something. Besides, most of the error messages have to do with self-checkout being implemented badly, and are not inherently an issue with self-checkout.
Ideally, self-checkout would work well, and in the ideally rare case where it doesn’t work, a person would be called automatically to deal with the issue and provided with a descriptive error which they know how to deal with. In this case, I believe the cashier job could be replaced with self-checkout.
Of course they are. Never let a good crisis go to waste.