As a C++ developer Rust's borrow checker is very interesting - it promises to solve my issues with C++ without the issues that make other languages (ie Java, Python...) have in the real world. (remember we choose C++ for a reason, Java isn't correct for our application - if Java is correct you should use that instead)
If you learn Rust, you'll find that you'd choose it over C/++ even without the brrow checker. Every little part of the development experience is just so much better.
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.