How does one qualify how much a language needs to be used?

Are you saying Rust is being used in places that you feel C/C++ should be used, and you don’t think Rust belongs? Or maybe you are saying Rust is being used in places where C/C++ are not typically used, and you don’t feel it belongs there?

The closest thing to context you’ve given is that you feel Rust has flaws (all languages do), and that Ada is perhaps safer. It’s really hard to give any kind of answer without a properly fleshed out question.

Overused

What is the correct amount of usage? Why shouldn’t people use the languages they want to?