* Not end-to-end encrypted by default.

* No end-to-end encryption for groups.

* No end-to-end encryption for desktop meaning normal use when working on computer requires you and your friends to constantly whip out phone to send 1:1 secret chats. Nobody wants to do that so they revert to non-E2EE chats.

* Terrible track record with end-to-end encryption deployment from AES-IGE to IND-CCA vulnerabilities

* CEO pretends to be exiled from Russia but in secretly visits Russia over SIXTY times in 10 years https://kyivindependent.com/kremlingram-investigation-durov/

* Zero metadata protection from server

* Open source, but it's meaningless as it only confirms the client doesn't protect content or metadata from the server.

I think Signal is a better alternative, even though it's US made. It's open source.