Comment by CobrastanJorji

Wasn't it obvious? One of Amazon's founding focuses was "make it stupidly easy to pay us." They went overboard to make it easy to buy things. The most obvious is their infamously patented "one click" purchasing, but there were lots of other things. For example, in the early days, they would let you create as many accounts with the same email address as you wanted because "sorry, an account with that email already exists" was an error that might keep you from purchasing.

The Amazon stores were the ultimate physical expression of this ideal. Walk into a store, pick up what you want, wave your hand vaguely at a scanner, leave. If they could have reliably gotten your ID without your involvement at all, they would've done that instead, but the hand scanner was the closest they could come.

There's nothing malicious about it. They just want you to be able to consume as easily as possible with as little friction or opportunities for second thoughts as possible.