I disagree. They are as portable as the code is, yes they might only work with a single language requiring another "format" for other linters in other language

I disagree. They are as portable as the code is, yes they might only work with a single language requiring another "format" for other linters in other languages, but they will stay with the code wherever it goes. And they aren't "uglifying" the code any more than type annotations or variable names. They are an additional hint to the user and the system about what a specific line or block of code is doing. They are just an annotation that the compiler ignores (for the most part).