Don't think nostr relays need to be in the phone, I think it's just as a bad idea as a LN node in the phone, but big Nostr relays will sooner or later end, and it's ok and good for Nostr and Nostr will be fine, what we will need to worry about is regimes scrapping nostr relays seeing some notes they don't like and matching the npub with your identity.
Discussion
I disagree. A local relay to hold drafts and store your notes is a great idea. A lightning node is not a good idea I'm the phone. nostr does not rely on the entire protocol being in sync.
On the topic of nostr relay censorship, after telegram topic, local only relays don't apply to this use case, you still need to connect to public relays.
public relays don't need to hold any content except for profiles, relay lists and maybe follow and mute lists... seriously... it's just a matter of those relays on those relay lists being reachable and clients having auth and the relay automatically allowing read access to your follows and voila, nazi commie governments can go fuck themselves
a relay is just a database, it makes no sense to reinvent the wheel, they just should be in every client or able to connect to one
that's what citrine is, nostrudel has the capability