A challenge for nostr is to be able to use it securely with multiple devices. I want to be able to save something on my desktop. And have it show up on my laptop. Edit on my laptop and have it show up on my phone. But I dont want to give my master key to my phone which may be left on a table etc. Each device needs it's own key. But they should be LINKED together, so that the app can know they are part of a key ring. Seems a valuable use case that has yet to be solved... Let's fix it!