I’ve always liked this, it has pretty much everything you could want in a personal project: a catchy name and a whimsical idea that is just on the edge of being actually practical.

This basically just means the files themselves become the authentication.

I don’t see a singe use-case, where you couldn’t just use normal private-key encryption and just save the private key to a file somewhere else. And if you want to distribute it to multiple locations, so that you need all of them, then there are also encryption methods for that.