Maybe, but if I want to privately talk to randos from the internet, then using my phone number like with Signal is a no-go from the start. Threema is paid and only partially open source.

Session is fully decentralised and while you can think of crypto whatever, at least it gives people the incentive to run nodes, unlike Tor where the incentives are all over the place, or centralised messengers which are fully reliant on one entity.