Signal has 100 million installs on Android alone. Arresting people for having Signal installed is not a scalable approach for a totalitarian state.
And while you'd think that senseless violence against civilians do not scale, times of civil protests in totalitarian regimes is not good time to be naive.
Shutting down routing for the entire country is pretty much par for the course. There's not such thing as collateral damage when the regime itself gets scared.
Not all of those are in the same country, though, and it’s worth thinking about how the install base would change after a particular country banned an app. The first time someone gets an official warning a lot of people are going to say “not worth it”.