I had to go to one to return a package. I couldn't get past the turnstiles because I don't use the app and don't know my password because I use a password manager. This meant I couldn't hand my parcel in at the counter.
The woman on the turnstile wouldn't let me in even when I explained the situation. So she went off and got a scanner to take my package. She didn't offer a receipt, and when I asked for one said it wasn't possible to give me one. I checked my email, and nothing there either. So I had no evidence I'd actually returned my item and she just said something like "It's in the system and never makes a mistake" or some similar rubbish.
While I was in there I saw several people walk just inside, faff around on their phones for 5 minutes then either give up or eventually get past the turnstiles. There's literally no benefit for customers unless you're shopping at busy times.
So all in all an unmitigated disaster.