Just replaces the card
It seems to me that this can just be used to replace the bank card. You swipe your hand and then type in a PIN. No different to now except you don't need to carry a card around. That would seem to be a sensible development.
For airport security, replacing a boarding card with a hand swipe seems reasonable too - you have your passport and hand rather than passport and printed piece of paper.
Just a different method of "something you have and something you know".