"no user profile IDs of any kind, not even random numbers, cryptographic keys or hashes that identify the users"
I still don't like this and I will keep harping on this. If users have no ID they cannot be reached. SimpleX offers multiple, separate IDs per user to inhibit correlation and controls for users over their IDs.
What's worse is that it implies that user IDs are a bad thing. They are the essence of users being able to maintain long-term online relationships and build reputation. We need more of that not less.