I think at this point it should be clear that the main use of blockchains is fraud.
If you are generally interested in decentralized systems and peer-to-peer systems, you will get a lot further with other protocols, some already mentioned in this thread. One I find particularly interesting is due to its relative simplicity is:
And I know some of the goblins people and one has been implementing OCapN in zig recently (incidentally, OCapN is also designed in part by Christine, one of the people behind ActivityPub)