It's becoming increasingly common. Rust is my first systems programming language too. I tried to learn C a few years ago but I found it too austere and prickly, which put me off.

That boolean is actually mostly an extension of the integer system whereby we now have an integer type that stores only one bit.

Whereby the bit stored either results in a 'true' or 'false' value.

Anyways, I know booleans are useful in systems development when you have strict memory / storage constrains / bandwidth (networks).

Yeah, that works for me.