I don't use them for a couple of reasons. The first being that I don't know how to use them and it takes me a long time and a large effort to do new stuff. It took me a few years before I was able to use "Chip & Pin" cards and instead used a cashpoint to withdraw money before entering the shop. The second is that I feel I'm helping keep people in employment.
I do get what you mean though. I like a short, polite conversation with the cashier but sometimes they can be very over-familiar and it seems to be that young men are the worst for this. The other day, the young male cashier was getting all chatty and using slang, like I was his friend or something. I had real trouble understanding what he was talking about several times. For instance, he said something like "Are you looking forward to the damage?". I looked at him quizzically and he just repeated himself. I asked what he was talking about and apparently he was asking if I was looking forward to paying for my goods! Why the hell would he ask that and why use those words!
Another irritant is when they ask scripted questions like "Do you need some bags" when they can see I have several bags. I know they have to ask these stupid questions, but it's still annoying. I love to pack quickly enough so that I can hand them my points-card/club-card before they can ask for it 
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Diagnosed: Asperger's Syndrome (ICD-10)
Self-Diagnosed: Aphantasia
Your neurodiverse (Aspie) score: 152 of 200
Your neurotypical (non-autistic) score: 46 of 200
Listener of all things noisy, viewer of all things bloody, writer of all things sh*t.