Paying with your phone works on the presumption that your phone is locked and you accept responsibility for ensuring your phone wasn’t breached. It uses contactless technology, but it’s still effectively chip and pin as far as your bank is concerned.

Meanwhile, paying with a contactless card is processed as “cardholder not present” where the seller assumes de facto liability and must prove otherwise. Contactless payments were never a new type of card processing, it was a new method but is categorised the same as when mail/phone ordering from a catalogue. The same with online purchases. They were always a step below card & signature or chip & pin. Paying with your phone is the same as chip & pin though, where the onus is on you to ensure the transaction is secure.

Paying with your hand has all sorts of issues making it impractical. You would definitely need an additional confirmation eg PIN, but claiming that your hand is as secure as a traditional card doesn’t lend well to pinning the liability on you. So banks are unlikely to use it.