One question I have about the automated checkouts at my local supermarket is they seem to intentionally slow the user down. For example, if you go to pay and pu

One question I have about the automated checkouts at my local supermarket is they seem to intentionally slow the user down. For example, if you go to pay and put in a card, it says 'please remove your card, press the -debit card- button, and pay with your card' It seems like no reasonable person wouldn't notice this flaw, let alone the presumably several people involved in creating this software, so it leads me to believe that there is some reason the shops want to encourage not using these checkouts. I wonder why?