I think Nostr can be the real Web 3.0, aka https://en.m.wikipedia.org/wiki/Semantic_Web as opposed to Web3 which I see as marketing hype for blockchain tokens. In regards to migration, a Nostr profile is truly portable because the signed events can exist on any relay. There is a trade off though, because a compromised private key means starting over.

Just for the microblogging aspect, there's probably not a compelling reason to switch platforms again when running your own instance already gives you the benefit of being in control of your data and online identity.

It will be interesting to see how the "other stuff" side of Nostr develops, where it can offer alternatives to all kinds of centralized media and commerce apps.