I disagree with the article you linked. It seems the author believes the purpose of decentralization was to give instance admins "power". I've always said that the Fediverse was just a thousand little Twitters, but some people don't mind that at all. If you just want to run a little community where you can protect yourself from outsiders I guess it's nice.
The way I see it decentralization is about preventing a gatekeeper not making more of them. If you never got your account (and all the content and followers you created with it) taken away by a power tripping moderator you may not understand. You can't deplatform someone from Bluesky, or Nostr, and that is a feature.