It is great.

But it didn't prevent Facebook from trying to abuse WhatsApp users in every conceivable other way including some rather innovative ones as seen recently.

Also it didn't prevent Signal from releasing a desktop client with a really nasty XSS bug and the phone client hasn't exactly been without faults either.

You and Moxie are both much smarter than me but I foresaw and maybe even predicted (possibly so early it is under another handle) some of Facebooks actions while everyone else was just talking about how E2E-encryption was the big difference.

This feels more or less the same: the intent is honorable, the core code is clever and almost unbreakable - but you cannot really trust all of the actors you need to trust for the system to work.

We cannot read WhatsApp messages in transit. And, as specified this system sounds good. But WhatsApp happily uploads unencrypted copies to Google Cloud and/or iCloud without your consent if another participant enable backups, and I'm fairly sure we'll see this system containing huge opportunities for abuse by power hungry regimes as well as one or two nasty bugs that has the possibility to utterly destroy a few innocent persons lives.