This is not what I am thinking. Problem with these is that they can be redeemed at the mint and then passed to another person without him knowing. Maybe the token should be put inside in some way so that you should destroy the note in order to redeem it. The use case that I am thinking is the normal use case of paper (physical paper) money, like passing them to another person. And on top of that whatever is technically possible as enhancement, like ability to check if this note is backed by real bitcoin and possibly redeeming it (by destroying the note as I said).