In theory it can be used on Windows, but I have no idea why anyone would want to.
It'll not beat madVR, there is years of development to catch up on there, and the new one is based on OpenGL, which is not ideal on Windows, DirectX is usually faster and more reliable.
Plus, at least at first, the new OpenGL playback engine will severely lack features, and will need months to catch up to the Red October/DirectShow stuff.