That's a good way of looking at it.

Bitcoin gives you a view on a shared global ledger, and you can run your own node to verify that ledger.

Nostr gives you ability to converse freely. Or to help others converse freely. Anyone can run a relay, but you dont have to run a relay.

The difference is, bitcoin is one single ledger state. Nostr is sharded into many thousands or millions of conversations, that can be independent of each other.