I think what the author means is that a Windows enabled tablet could replace the laptop space.
On your work desk, it's connected to an external mouse, keyboard and monitor - desktop mode
When you go to a meeting, or go on the road, you take the tablet with you - mobile mode
The advance here is that you're running the same apps (yes, Word, Excel, legacy apps), same logon, same computer... whereever you go. In the corporate world, this could be huge.