Extremely wide support for one. CMake is the only build system with first class support for all of the major platforms - and those platforms' default tooling.

Extremely wide support for one. CMake is the only build system with first class support for all of the major platforms - and those platforms' default tooling. I can't tell you how much Visual Studio adding CMake support reduced the barrier to support cross platform C++ projects. I'm a Linux user myself, but I interact with a lot of Windows developers and telling them to leave Visual Studio and use command line tools usually just means they won't be happy about working on a project.