cmake's value is in the way it provides a high-level abstraction over all supported platflom's capabilities, and that it works by generating and running build scripts from lower level systems such as standard make.

For example, Cmake allows us to set the version of c++ a project uses with a single build target property, which is then used to pick which compiler's flags it uses with a given compiler. It then generates the makefile with all the relevant flags set, and runs that with ease.

This works regardless of platform or compiler.