Currently, Nostr is more or less very niche ; with currently around 2M registered users, and probably 10% of this as daily active users, it has great potentials, and also many bugs ; an annoying issue with a bot spamming the relays.

The current web client (primal) is not optimal yet, it is slow, searches are missing, let's say it is not helping the adoption by people use to facebook or Twitter/X, yet ...