What do you code in Rust?

I've only been coding with Python/Javascript since I started my career. I do APIs and websites frontend. I don't really understand what is interesting in learning an other language. For example, I could learn Ruby, but I'd do the same thing I already do.

Rust, C/C++ tho seem to me to be languages to code other things. Hence my question : what do you code? If possible, make distinction between personal projects and professional projects.