I can run Postgres with no cryptobro crap required. Huge advantage. If people don't want to trust my instance, then we can start signing blobs so my instance only shovels dumb data around that anybody can verify being authentic. If relationships are required to be verifiable, we can build a PKI.
If you could build PKI in a decentralized, privacy preserving manner for all internet users that’d be huge. So far no-one succeeded.