The Super-Walmart where I shop for my elderly mother used to be a checkout nightmare. With my bad hips, waiting in line for as much as 20+ minutes was often too much. I would have to leave my spot in line and go sit down for 5-10 minutes and then get back in line and hope for the best, rinse and repeat.
A few weeks back they decided to go self-checkout in a huge way. Now, there is zero wait time to checkout.

My old, painful hips love it!

I did have one problem a week back with the self-checkout scale adding ~2 pounds to my weighed items. Fortunately, I noticed it and they moved me to a different machine to finish my order. They could not fix the faulty scale in real time.
Well, do you think they took that self-checkout with the faulty scale out-of-service until it could be fixed? Nope!
I tried to warn the next customers they sent to that self-checkout, but apparently they didn't speak or understand English.