The real problem with it that it doesn't provide solution to anything beside being a very nice gimmick, you can't really transfer bitcoins to someone offline with those bills, as you will need to trust the bills/coins issuer that the bills/coins do really contain bitcoins and have never been opened.
Trust is indeed the main issue in that case, but it offers a great alternative in my opinion. I ordered a dozen of non funded Denarium physical coins lately that I might load at some point just in case. Initially my purpose is to hold them as collectible, but it might turn out to become helpful later on as well if someone is willing to trust me enough to accept it as payment.
Technically it's impossible to have a perfect emergency//no internet payment solution, especially when fiat no longer holds value due to the imploding financial system. Gold and some other metals are the only things left, but how will you turn your 100 gram Gold bar into $3 worth to buy a loaf of bread or whatever? I am fairly sure that eventually something will pop up taking care of the trust issue of exchanging private keys in a way that tops everything we have right now.
