If they want to make it effective for the consumer it better be personal/ID specific like you stated and usable between devices. It could also be so subcontanious it would be a military/gov enhancement to imo.
It's so carry-over error centric I don't think they can make it work, and 'to trust it if they do' is the question... Can imagine the query needed just to verify.
e.Digital definitly needs to ie this platform
or build it, show it off
e