Hmm, I can't read DK, but I suppose it could work. Issuer loads coin to private key, prints address on bill, so you can check if the coin is still there.

BUT ... Its a horrible trust issue though. Does the issuer destroy the private key (in which case the bill is just fiat), or hold it in safe keeping for redemption? And what if the issuer cheats and cashes in down the line, or goes bankrupt and the court demands private keys so as to pay creditors.

What would the fed (or eurobank) have to say about it? Fed has prosecuted private coin issuers in the past.