no one uses xmpp, and it doesnt have cryptography natively….
not all implementations integrate with omemo and its ass and ugly and annoying, plus again no one uses it
Whats the problem with Signal? also there's p2p fork of Signal… not a great idea but also federated servers take effort so i guess for most people centralized makes sense here, its not optimal but fr what did Signal do to compromise security? they do real e2ee that is supposedly authenticated on each client, and its open source afaik so whats the deal
no matter what your metadata is fucked pretty much
also xmpp is federated too… so its also kinda ass for that