You can get effectively the same thing via "Scan & Go" technology. Here in Australia, one of our two main supermarkets has it. You download their app, and when you enter one of the stores that supports it, you click the "Scan & Go" button in the app, and then scan the barcode of things you want to buy (or scan the digital scales after weighing your fresh produce), and then when you leave, you click pay, scan your phone, and walk out. It sounds way worse when I explain it like that than it really is. In reality, it's enormously convenient and I will now go out of my way to go to one of these stores rather than the competitors which don't support it. It's only been here for about a year now, but according to this video something similar (using a specific hand scanner, rather than a phone app) has been around in the Netherlands for at least 5 years.

And if I'm reading the article correctly, even these Amazon stores already support the same kind of thing.

So as cool as it would be for convenience if this really worked purely through technology, that technology is not needed to reduce the labour required in supermarkets.