[PKop]

Without looking at details too much, it's seems significantly different than paper claims on a separate physical asset held by a custodian 3rd party subject to counter-party risk.

The control of the BTC is maintained with possession of the private key stored in the bearer asset cash.

Holding gold certificates does not enforce any fundamental claim or control of the actual asset the backs the paper; possession of the physical gold does. You need to trust somehow that the holder will exchange the gold for the paper in the future, as well as actually have the gold at that time.

[yoavm]

Well, here you need to trust that their app will exist next year. And perhaps also that something will happen when you cut the notes, but I'm not sure I got that part...

I don't know if it exactly like gold certificates, but it sounds pretty close to "I'll pay you with cashews" to me. It's not terrible - I bet a many people exchange goods like this every day.