> because almost nobody stands in a line to have somebody else scan your shopping, why would you? A decently trained human can scan & bag far faster than I can

> because almost nobody stands in a line to have somebody else scan your shopping, why would you? A decently trained human can scan & bag far faster than I can at the self-checkouts. The self-checkout machines are also sometimes buggy. Our local Safeway's self-checkout was extremely particular: if you scanned the next item prior to the computer registering and processing the weight from the previous item being set down, it would error out and require an attendant. That processing was quite slow — so you needed to lag yourself / rate limit yourself, so as to allow the machine time to think, before proceeding. I eventually figured out the cadence to go, such that I could avoid the error … but humans just don't have this issue. Items too light to be detected just always error on some of these machines.