For the last few weeks, I've been trying to come up with a reason why anyone would want to use Microsoft Windows for projects on the Raspberry Pi 2. I can't. In fact, the more I think about it, the more it seems like this is just another 'us too' move by Microsoft.
Think about it: you're not going to run the full desktop version of Windows 10 on the Pi. It's simply not powerful enough to do that and have any kind of usable system. That means you're likely going to have to run a command line version of Windows and, really, for the most part, Windows users are terrified of the command line. That alone is going to knock out a good segment of potential users.
Next, let's look at the tinkerers. Those people are generally not afraid to get their hands dirty and mess with the underlying OS, including using the command line. Those people are likely not using Windows for their current projects because it lacks the one thing they crave: control. They're using Linux.
Once upon a time, one could make the argument that the benefit of using Windows on these type projects might be having the ability to code in C#. With the open sourcing of the core .NET framework and the progress open source projects like Mono have made, that's not compelling. Plus, let's be honest, even if you couldn't use .NET, any programmer who's learned C# or any other major programming language could pick up enough Python in a weekend to do most or all of their Pi based project.
No, there just isn't a single reason I can think of to use Windows on the Pi instead of Linux. Microsoft would be better off giving up on Windows on the Pi and focus on making some really compelling add-ons for the device. Like, maybe, bring Kinect to it? Now that would be useful.