Self-service checkout at the store exit is such a wasted opportunity. In my (non-USA) grocery store I can scan product with my phone while I'm walking through the store and putting them in the cart; afterwards I only have to pay. Not having to take everything from my cart, scan it and put it back saves quite some time, even compared to cashiers scanning. There's also a handheld scanner for people that can't or don't want to use their smartphone.
I used such a system when I lived in Switzerland, and found it much easier for the reasons you mentioned.
I did have an odd conversation with someone at work who warned me that sometimes they check your basket to make sure you’ve scanned everything before leaving, which I thought was an odd way to tell someone you like to shoplift. Anyway.
