Cool, but the point of having stuff in Rust is to ideally have everything in Rust, or you're by definition not getting all the safety benefits of Rust.
- no undefined behavior
- many classes of concurrency bugs prevented by the type system
- standard library and much of the ecosystem makes invalid states unrepresentable. E.g. a String is always valid UTF8
Those are things that are true to varying degrees for other languages. Dart does pretty well imho. But for example Java and C# offer memory safety but have very unsafe concurrency
It does nothing to prevent data races between processes, or concurrency errors between threads accessing resources that are external to the process.
Scenarios quite relevant in distributed systems.
I do agree it helps, but it isn't the improvement over other memory safe languages, that the Rust Evagelism Strike Force makes it to be.