"Module::Build is the official heir apparent to MakeMaker and we encourage people to work on M::B rather than spending time improving MakeMaker." - ExtUtils::MakeMaker::FAQ.
While Module::Build does a nice job with modules, it really doesn't do a good job with applications. Simple things like creating a directory that is specified by the user and copying images/templates/configuration info/data files, are just a pain in the tail. So until Application::Install gets written, lots of us will be using MakeMaker.