I think multiple competing registries, including people hosting their own, is even better than a single community registry, so this is good.
The notion of centralization that registries imply is what makes them iffy — centralized human readable names is in opposition to the general nix philosophy of trustlessness and things being freely combinable (no collisions, no conflicts, etc.). Having multiple registries re-decentralizes things — unhappy someone is squatting a name? Just create your own registry! This is unambigiously good.
Also, I hope eventually at least one things don’t care about flakes at all. As we’ve discussed on the Nix Team, registries are a fetching concept, and fetching is conceptually prior to flakes (see WIP: Generalize the fetcher registry to not be flake specific by Ericson2314 · Pull Request #9085 · NixOS/nix · GitHub). Of course, I imagine it is good for registries to enforce additional structure — otherwise they are just a glorified bad version control — but there are many ways one might want to do that.