I think the original Bitcoin proposition had some merit in introducing a new concept and a new type of trustless economy. However probelms in scaling the PoW mechanism and transaction fees make it infeasible for daily use.
99.9% of the other stuff? Never understood why people see value in NFTs. Especially given that they mostly link to image files on someones web server that would point to a 404 page if taken offline.
Yes, ideally you‘d want to have a few large communties on each instance and not all topics with a single userbase on one. This not only decreases the load but also prevents scenarios in which a single admin starts to capsule their instance with a large userbase away from the federation.