What I think will be an interesting use case for this technology is public file sharing.

If I want to share files with the general public I could just give them a read-only key and then they'll have a folder that syncs with whatever files I put into it. It's a new way of content distribution.

Will this be how people distribute music and TV shows?

Will this be the way people subscribe to content in the future?

I could be a game developer, and I could give my users a read-only key to download my game and at the same time they'll receive any updates I make to the game when I update the files in the folder.