Why? Because I don't have one. And I don't see the point as a self-hosted user. But Apple keeps releasing things that can only be used with DotMac - and most programs only have rudimentary export features without DotMac implemented. I can understand that they also want to make money - but DotMac is just too limited for me, I can implement most of it myself much better. So give me a simple SFTP upload option and that's it ...