You don’t actually have to converse. I get by with ‘Hei’ and ‘Takk’ on most transactions, and sometimes just with a nod or two. You can go through the whole process without ever even looking up from your phone if you like.

And it doesn’t really go any faster. You still have to scan the same stuff, probably no faster than someone who has experience doing it every day as their job. You have to bag it, which sometimes can be done by a bagger in a normal lane, so parallelism grants possible speed there. The machines also have lag, sometimes not letting you scan your next item until the last one has nicely settled on the bagging scale. And if you want to buy an age-restricted item, or if there’s anything that doesn’t go perfectly, you have to wait for the human to come over and handle it anyway, which can be a long or a short wait, but still dead time.

Worst of all, though, is the machine talking at me. If you hate a cashier talking to you I don’t know how you can tolerate a machine making you listen to it explain how to do the painfully obvious, while simultaneously preventing you from doing the thing you aren’t being paid to do. That part alone generally is going to make it slower than a normal cashier.