When you say "Rust enums are also enums", that's not true in general. What is true is that _some_ Rust "enums" (like your `Colour` example) can be represented as traditional enums. You don't prove a universal quantification with a single example.

More than that:

    #[derive(Debug)]
    enum Colour {
        Red = 1,
        Blue = 2,
        Green = 4,
    }

    fn main() {
        println!("{:?}", Colour::Blue);
        println!("{}", Colour::Blue as u8);
    }