A credit card is for gaining access to the electronic payment monopoly's network[1]. BNPL is explicitly a loan. Yes, a credit card transaction may effectively turn into BNPL if you fail to complete your end of the transaction in a timely manner, but that is a hindsight outcome, not the reason for choosing the method in the first place.

[1] Nowadays you can often also use the network with other methods, like a debit card, but those alternatives still aren't universally accepted like credit cards are.