given the general attitudes towards privacy and biometric data here on HN, i honestly can't tell if people trying to pay for groceries with bloody severed limbs is a concern you legitimately have or if this is satire.
Comparing this system to, for instance a chip card reader, the palm print is significantly less secure because it uses a single factor (something you are) versus a chip which requires the customer to both have the card with the chip present for payment, and to know the PIN in order to authenticate. Or your phone for example, if someone steals your fingerprint (or even models your face), they still need to have your physical phone to unlock it. With this palm scanning tech, all you need is the palm and you can pay for anything anywhere because there's no secondary confirmation