A robot is made of dozen, if not hundreds of packages. catkin compiles the whole workspace in a single command while dealing with non trivial build dependency between packages, and generates a ready to deploy folder.

CMake has its drawbacks, fair enough, but 10 years ago it was pretty much already the de facto standard build system for C++. What would have used instead of CMake ?

  - Make and autotools (Haha) ? 
  - scons ?
  - completely custom build system ?
  - something else ?

The most painful I had to deal with was my teammates who, instead of creating a brand new package, would simply copy and paste and existing one without fixing the dependencies, resulting in a build that fails if the workspace was cleared.