There's no guarantee that the tablet would ship with Windows 10 support out of the box. As with Android apps, it might take some time before it's ready. This could be one of the first devices with the extra option, though. It would make sense for Google to go first. The Pixelbook and its ancestors have frequently served as showcases for the latest Chrome OS features, not to mention reference devices for developers. So long as the tablet ships in the first place, it could serve as a testbed for anyone who wants to know how Chrome OS and Windows can coexist -- and an option for enthusiasts who aren't quite sure they can live with Chrome OS by itself.