The real Windows RT advantage
When you buy an app on your iPad or Android tablet, that is where it stays. I hope you always like iPads or Android because if you ever decide to shift from it, you have just wasted all of that money on apps you will never use again.
When you buy an app on your Windows RT tablet, that app will work on any Windows 8 device you have as well. So if you ever decide for whatever reason to shift from Windows RT, no worries, you can still run it on your laptop or desktop. If you decide to never shift, you still have the choice of running those same apps on all of your devices, no matter their formfactor.