Oddbean new post about login | logout I don't necessarily think so. But everything depends on your threat model. For most people it is safe enough, besides being difficult to even get people to use Signal, it would be damn near impossible to get normies on SimpleX or Threema.
That has absolutely been my experience. I'm getting them on my self-hosted Snikket, though, somehow. It's like a glitch in their programming.
If your threat model includes people breaking down your door and interrogating (torturing) you, the messaging app or security don’t really matter since you’ll give them anyway. Shamir secret sharing is used by companies that needs security, along with guards, double entrance security doors, offline / airgapped devices, etc…