Meh - I was excited by JWO but it now looks like self-checkout will win because it works pretty well these days, and it handles all the corner cases including product sold by weight, large items, identical-looking items (common in grocery), etc. With self-checkout, you don't need an account which is crucial for travelers. Self-checkout also supports cash for the unbanked. I've tried SC in multiple countries, just hit…
I've stopped using self-checkout because I always run into troubles. In one store when I accidentally double-scan an item, I have to press the button to call someone, and it takes 5 minutes for someone to show up. In another store you need to place your groceries onto a weighing shelf, and somehow I couldn't figure out what to do to make the machine happy. For produce and pastries that don't have a bar code you have…
Kroger's self-checkout is absolutely obnoxious, they've hooked it into some machine-vision stuff to try and stop you from stealing, but it literally stops you about every third item no matter what you do.