Many of my cards are just repurposed from other things. Lots of hotel keycards can be rewritten to open URLs on phones for example.
I actually have a hotel keycard taped to my washing machine to do some laundry-based automation with my phone. Maybe I should write about that sometime..
If you're getting an implant already, why not make it an actual smartcard that you can use for WebAuthN, GPG, SSH etc.? :)
On the other hand, the fear of permanently bricking it or messing up the GlobalPlatform card management key has so far prevented me from doing it myself...
Because those cost $350 as opposed to $89, and the install only costs $60, and there is no stopping you from implanting more than one in different locations.
Many people get the small xEM or xM1 first to play with.
I actually have a hotel keycard taped to my washing machine to do some laundry-based automation with my phone. Maybe I should write about that sometime..