The interesting thing about Nostr (vs each of the other options listed here) is that it works perfectly fine over sneakernet. And that has been impossible to block throughout the world, even in some of the most oppressive nations.

Since the spec includes identity, content (in multiple formats), and authenticity/integrity, this makes it superior to nearly all alternatives for offline use. Once you know someone’s key, you can verify that content comes from them, however you manage to obtain that content.