@anne_twain @Gustodon @georgepenney have you ever tried it? It's actually amazing.
When you get an item, you scan it, and put it straight into your bag. It takes an extra 5 seconds per item, and when you're done the entire checkout process start to finish takes less than a minute. You don't have to unpack your trolley and then repack it into bags; you just swipe the scanner, pay, and walk right out of the store. It's so much faster and more convenient than waiting in line for a teller.