Reminds me of store self-checkout scanning machines. A lot of the time, they aren't actually
faster than waiting in one of the staffed checkout queues—especially if they have a queue themselves, as customers operating the machines are inevitably less experienced at it than the cashiers are at operating the POS.
But people still prefer them. Why? I think it's a social anxiety thing. You don't want to think that you're wasting someone's time on your goods—showing them what you've bought, having them fuss over each item and acknowledge that you bought that—when you could instead check yourself out in relative anonymity. You don't have to make any small-talk, or even take out your headphones if you don't want to. It's really about eliminating the "friction" of the social norms involved with the manual checkout process as much as it is about automating anything.