This is part of my problem with self-checkout. It seems like a good idea and I tried to use them years ago when they first cam out, but it seemed like I always got stuck behind someone who did not know how to use them or I would use it and it would malfunction (which could explain the issues other people seem to have in front of me). Then there are the ones where you self-checkout and then they want you to stop to make sure that you paid for all the items in your bags. When they do that, it really saves me no time, it just allows them to hire fewer employees.
I thought the point when they came out years ago was to make things more efficient and fast while also cutting their costs. But at this point, it's all about cutting their costs while making self-checkout inconvenient and slow for the customer.