The point is that I have my own secret key that I generated, but it's annoying and unsafe to paste it in Nostr apps everywhere -- and we want people to use multiple apps for multiple tasks, all with the same identity. So the solution is to have the NIP-46 bunker thing that keeps listening for requests to sign coming from authorized apps. But I don't want to run such a bunker daemon, I have no idea of how to do it, it's annoying blablabla; therefore I want to delegate that task to some third-party to run this daemon for me. But I don't want to give this third-party my key, it would be much better if I could split my key in 3 once, give 1 shard to a different provider and trust that they won't collude to recreate my key -- but then they cooperate to sign stuff on my behalf and is as if it was me who signed it.