The top of the screen is filled with the the applicaiton name ("MY APPLICATION") and some text. In this case the "page name". While having this information occupy prime real estate may be good from a branding point of view, this could be seen as a waste.
Fortunately the UI guidelines give us a good reason for this behaviour:
Applications that expect user interaction during a phone call should have a minimum 75 pixel margin on the edge of the device that has the power button. No touchable UI elements should be placed within that margin.
It's a phone! People will want to make phone calls with it. If they can do this while still using your app, let them.
If you've built Windows Phone or Windows Store apps you can cross-promote them with AdDuplex to get more users.