Isn’t this just an implementation/UX issue? Ideally the root key should live somewhere secure (offline) and delegate keys live on connected devices. As the ecosystem matures I would expect this to become easier. A hardware wallet means the risk of key loss would become negligible.

I think CRDTs are great, but Nostr has always presented itself as a potentially lossy medium, purposefully. Unlike SSB and Matrix where state synchronization became a complex bottleneck, Nostr is more IRC-like. Relay owners may have to delete individual posts due to legal reasons, or identities may selectively publish different posts to different relays. The devs didn’t see this as a problem since full state synchronization is heavy and requires long term retention of data. I agree that it’s not perfect, the tradeoffs make it harder to reconstruct a full history for a given identity if you’re trying to reach way back in time. But for new content it works really well, and I think this is why they chose this approach. If you publish to a lot of relays, your message will get through to the people who want to see it, although the process is messy.