One of the features that Windows Mobile has over other phones is the ability to use Continuum, a stream from the device to a monitor to use it as a desktop. When docked, users can run Windows from their phone, controlled with keyboard and mouse on an alternative monitor. But even as it is a highlight, Continuum still has issues with some applications.
Unfortunately, the Netflix app is still having issues playing nicely with Continuum. So if you're running a Continuum compatible phone, you can at least watch videos through the browser now. Hopefully, a fix is in the works for the app down the line.