Did you pay cash?
The payment terminal is essentially not actually talking directly to the POS except to tell it that transaction id "xyz"(which only your bank/"card issuer" know is you) was approved, everything else is encrypted between terminal and payment processor and not supposed to be visible to the retailer.
I don't know if they store the card details directly or if they store a hash, but they certainly have a way to tie your credit card to the video of your face leaving the store and (most likely) a video of your license plate as you drive away.
Sell that to a data broker (as they certainly do in the US) and someone could potentially purchase a history of what you bought anywhere and when.