That change was driven by the drastic expansion is quantity and variety of goods. A person couldn't reasonably verbally dictate what they'd like to buy in a modern grocery store. It's far more convenient to choose them yourself

The driving factor for self-checkout was solely profit, not customer convenience. I, personally, find it far more convenient to have a cashier do the checkout, because they're far faster and the responsibility of doing it correctly is on them, not me. I don't want police showing up at my house because the AI at my grocery store incorrectly decided I stole

Look at all the people in this thread complaining about how slow other customers are in self-checkout. It's clearly a widespread issue