I'll tell you exactly how: trying to maintain cross platform ITK builds on tons of bespoke HPC clusters and academic workstations using the existing build tools

I'll tell you exactly how: trying to maintain cross platform ITK builds on tons of bespoke HPC clusters and academic workstations using the existing build tools became a nightmare. Writing makefiles is extremely repetitive and tedious and error prone: precisely the kind of thing to automate. Not just makefiles mind you, cmake is designed to automate all sorts of build parameters.