Hmmm, not all credit cards have a PIN. Debit card, I could see that. I don't know if the data on the card indicates if there is a PIN attached to the card (i.e. ask for it if there is, don't ask if there's not).
The card and terminal communicate on which CVMs (cardholder verification method) they support, and they agree on one. If they can't agree the transaction is either cancelled or processed as "no CVM" (like normal contactless tap & pay with a card) depending on the terminal's and card's risk profile.