The point for me to learn C or C++ over Rust is not to interface with an existing codebase, but gaining proficiency in reading & modifying it. You certainly wi

The point for me to learn C or C++ over Rust is not to interface with an existing codebase, but gaining proficiency in reading & modifying it. You certainly will also gain that proficiency simply by learning Rust to some degree, but I think it helps to have written both C and C++ to be more fluent. If that is necessary greatly depends on your needs. I rarely had to modify or read the actual code of libraries I used, but when I had to, I am not sure how I could have solved the problem otherwise. For me it is sometimes quicker to read the code, than treating it like a black-box and trying to figure out what is supposed to happen by often outdated documentation and examples.