> torrents need trackers but we still consider them peer to peer

false. there's DHT and we sometimes exchange magnet links with friends and trackers are optional. trackers just allow it easier and at scale.

> crypto needs nodes but we still consider them decentralized

It's only decentralized when somebody doesn't get to control enough nodes. Even if it was decentralized, it's apples to oranges. It's not serverless or peer to peer and this messenger is not distributed.