In case you don't know, @cwtch is a decentralized end to end encrypted chat app
there's no servers by default, meaning no central authority
transport is based completely on Tor onion services, which itself is decentralized and provides automatic and transparent end to end encryption
(though @torproject still hasn't deployed any post-quantum cryptography into Tor, Cwtch is not as robust as newer PQ Signal or iMessage)
the profile ID that you share with your people is based on the Tor onion address that your profile is using for communications. if you shut down Cwtch, your Tor onion address also gets shut down, so you can't receive messages while you're offline, by default
it's my opinion that using Tor onion services for chat apps is a no-brainer. everyone with a Cwtch profile is both a client and a server. you are your own server. because of how Tor onion services works, as a reverse proxy, you don't need to host a "public" service on the internet. and e2ee, key management, encryption is all automatic. you can't fuck it up! its crazy to me that apps like Matrix don't take advantage of this. Tor onion services is an extremely powerful tool and so many people ignore or think of FUD