Considering Rust's target audience, I think comparing Rust to scripting languages is ok. While Rust is aiming to compete in the system programming arena, it also aims to allow programmers who have experience using higher level languages to be able to get into systems programming without having to worry about safety. Rust has many features that make it almost feel like a high-level language and thus makes it much more approachable. That being said, Rust does not aim to really replace Ruby/PHP or Javascript, but rather a be a tool available to those programmers to write fast and safe code when needed.