In many places it's also possibly just a left over feature from older times. I worked at a major UK supermarket in the mid-00s, and their checkout system had this feature. But it was like that because that's how it was originally built, it wasn't a 'feature' they added.

Credit card information would be recorded by the POS, synced to a mini-server in the back office (using store-and-forward to handle network issues) and then in a batch process overnight, sent to HQ where the payment was processed.

It wasn't until chip-and-PIN was rolled out that they started supporting "online" (i.e. processed then and there) card transactions, and even then the old method still worked if there was a network issues or power failure (all POSes has their own UPS).

The only real risk at the time was that someone tried to pay with a cancelled credit card - the bank would always honour the payment otherwise. But that was pretty uncommon back then, as you'd have to phone your bank to do it, not just press a button in an app.