Hm, I'm not a fan of Cmake. I like how simple and clean Make is. In my experience it works more often than Cmake, and if not, I can usually debug it. Cmake seems like an overengineered beast to me. But I probably haven't 'grokked' it yet.
The ability to have the entire build/build artifacts in a directory completely standalone from the source directories was a huge win.
Because for me, that meant I could have 3 separate build directories - one for my optimized ARM builds, one for my debug (-g -O0) ARM builds, and one for my x86 unit test/coverage builds.
If I modified one file, I didn't need to re-spin 3 clean builds - I just could hop into the one or more build directory I was interested in and incrementally update the builds. Plus, out-of-source builds make building clean as easy as `rm -rf build/` instead of hoping that `make clean` has all the right pattern matching and subdirectory listings to truly scrub the build artifacts.
[1] https://cgold.readthedocs.io/en/latest/tutorials/out-of-sour...