Probably it's lack of infrastructure buy-in. And personally, I find the misuse of the word biometric in the white paper off-putting, along with the lack of detail on the basis for the technique. The fingerprint is somehow related to the magnetic particle distribution--how stable is it against weak magnetic fields, or against heat?

If you really can reliably get magnetic signatures, it would be really hard to clone cards.

Edit: the particles won't really change, but their magnetic states feasibly could