It matters to me, because I want to reach out to users on Windows, because I think that will help create momentum so books, videos, forums, websites and so get created. The top three suggestions Google gives when typing "krita " are "krita download", "krita vs gimp" and "krita windows". There's a demand, for Krita at least, on Windows. I just need to figure out a way to get there, preferably without going mad.
It's the same problem apps like gimp have, of course. Gimp has many, many more users on Windows than on Linux and not a single Windows developer.