The point is that, if Signal goes bad/evil, someone can just take the code and self host it. I don’t need a federated service. I want a messenger that has powerful end to end encryption with forward secrecy, post-compromise recovery, deniability, and post quantum encryption. Other social media, like Mastodon and Lemmy, don’t have encryption because everything is public anyway, and I value decentralization more about them to avoid political interference and censorship (which are irrelevant on Signal).