If you don't want your payments to be tracked you need to use cash or crypto. Otherwise, just use a credit card. I really don't see how unlocking a phone is easier or more convenient than using a credit card.

The watch is on my wrist, or the phone is already in my hand. The credit card is buried in a wallet that needs to be taken out of and put back into a pocket.

Also “unlocking” isn’t an inconvenient step, on iPhone it just happens automatically. As it should on android if the fingerprint sensor is in a convenient location.