The card issuers are afraid people will forget their PIN, since most people have only one ATM card but multiple credit cards. And if one CC provider requires a

The card issuers are afraid people will forget their PIN, since most people have only one ATM card but multiple credit cards. And if one CC provider requires a PIN, but another one doesn't, then the customer will put the card back in their wallet and pull out another card. Or they will not switch between cards, and consolidate to only one card (whereas a lot of people pull out a credit card at random, apparently).