It's not though. It's fast enough for many applications but if you need to write a hypervisor then suddenly bounds checks and atomic pointers become significant. Not to mention that rust dramatically reduces your ability to control where memory is allocated.

I write in rust and c++, rust isn't as fast. Rust is easier to work with and, compared to the Java crap it's replacing at my work, it's a lot better but it's certainly not zero cost abstractions the way c++ can be, nor is it great for data oriented design because you're hoping the compiler will do the right thing, consistently.