Cards can have nfc, and most people already have nfc readers in the form of phones. I think this is the easiest way to support cryptographic payments.
Someone else said the number is 'hidden' from the users but it's not hiding versus not hiding that's the problem. It's that for e-commerce the human has to transcribe the number by hand. You can't hide it, except via another system.
AFAIK, that's how the first version of 3D secure worked: you were redirected to your bank site and authenticated the payment there.
Meanwhile, with my Samsung phone and its mag strip emulation, I can use my phone nearly everywhere anyway even if the store doesn't want to support NFC.
During the pandemic, I haven't used cash for the last 6 months.