> Some sites only require re-entering the card when shipping to a new address.

This is what Amazon does, in my experience.

Yah I think it's a good thing. I have a password manager so it's only a few clicks to paste the card number in. I'm guessing the majority of consumers are annoyed by it.

amazon has required me to re-enter card numbers when shipping to an address not associated with that card. I have bought on Amazon in the US, Spain and Mexico with this happening each time.