Oh the alternative isn't taking a credit card out of my wallet and all that. It's scanning my Amazon Prime QR code and then tapping my watch after selecting the credit card. But it isn't "hard" per-se, just mildly inconvenient, and yes it doesn't take much inconvenience for me to volunteer my biometrics. Clearly that isn't sufficiently common a position or they wouldn't be removing it so your surprise is likely quite common as well.

It's another small source of friction. I don't know if biometrics are the solution, but I do find for example that I'm much more comfortable buying on a website I've used before and already has my card details, rather than giving them to a new website.

The useful data in that story is the eating and shopping habits collected by the transaction. What are they going to do with the arrangement of lines on your palm, likely stored as a compressed latent vector not useful for reconstruction?