I would argue that The Matrix.org Foundation (npub1m9z…whzq) / Element (npub1tcc…4342) is a better signal replacement, and that blog post is wrong.
The option for unencrypted rooms is for interoperability that signal just does not have and such is not a real argument.
There is no automatic fallback to unencrypted messages as it is with xmpp or a wrong standard as it is with that russian network that must not be named.
Signal does not have reproducable builds and is not federated which makes it vulnarable.
