I disagree with the idea of allowing backup/restore of conversations defeats forward secrecy. There's a big difference between decrypting past conversations and decrypting chat logs. I have full control over my chat logs, I can choose to delete them, not store them with some people, encrypt them with a different password and rotate them monthly, etc.

Even Signal and other apps store all your messages on your device, optionally locally encrypted.

Forward secrecy is so that you can't just steal the key and network traffic and get _all_ past messages, regardless of whether or not I wanted to archive them. And getting my live key doesn't mean getting all my archived logs.