For better or worse CMake has become a de-facto standard. You can (justifiably) argue Meson is better but honestly CMake is "good enough" and a slightly saner build system is not worth the loss of "standardization".

For C and C++, if I'm not using CMake, then I'm using some cobbled together shell scripts that do precisely what I need, no more, no less.

But for libraries there's a huge benefit to CMake since you can create a Config.cmake file for other projects to easily add your project as a dependency.

Or to use with FetchContent for rather nice dependency management.

The syntax is horrible, the semantics confusing, the way to do anything correctly weird and unintuitive like those generator expressions or whatever they're called and how the Config.cmake file is supposed to be generated. It is hot garbage.

But I'll still use it because the alternative is making dependency management in C/C++ land even worse.