As an European, Amazon Go seems like extreme over-engineering, with its vision-based system and all. I can already quickly scan items as I put them in my basket, either using a handheld scanner you pick up at the entrance, or my own mobile phone. You can also do it all at once in the self-checkout station. It already takes little to no time, and simply adding a very fast barcode reader to the basket itself or RFID would completely eliminate any time spent there. Payment takes five seconds with contactless / Apple Pay. Most small supermarkets already have only one or two cashiers working at any time.