I think the new users are here to stay - and more are coming!
One huge shift I have seen is the WAX blockchain allowing users to sign up with just social, (using WAX cloud)
I think this (and others to come using the same idea) are going to be crucial to adoption, and yes, I think they will stay and more with come in groves.
Use cases are exploding, from SEEDS to NFTs like you say. More and more people are starting to get VALUE from the blockchain, like we all do writing here on Hive
The more value blockchain can provide, the more people will show up to benefit
I also agree it's not about a killer app, but they do help. I'm hoping when we shape up cxc.world (@currentxchange) it will be a big step, as we take non-blockchain content and add a layer of blockchain rewards on top (opposed to Hive, where you need to post new content)
Of course, Hive is the best example of the blockchain providing us value, and it's a huge case study for long-term benefit and user retention.