Seems like its intended to be a hub for sending things from your device to another device. Obviously the main vision is an analog to PlayTo where you're sending your screen to a compatible device, but they then include "sending" content to a printer and "sending" your desktop to a projector. "Sending" audio to a BT device seems like a fair comparison.
Of course all of this is only useful within metro apps, which is a head scratcher.
Personally I wouldn't be surprised to either see charms dumped entirely in Win9 or completely overhauled. Seems like a dud.