Well, I have to say you’re right about SAMSUNG. I never tried to use it on terminals without NFC, but now I’ve to try it.
As for the batteries, they are really batteries in pacemakers. It’s correct that batteries are somewhat dangerous if implanted, but those are ok. However, by now we could use wireless power transfer to power implanted devices which could open the door to a host of different implantable devices with more functionality than just transmitting a few KB data.
I talked about implanting solid state batteries here:
Solid State Battery as implant power source - Projects - Dangerous Things Forum