Yeah, it said that it utilizes the phone's GPS and carrier for things like calls and GPS, so yes, you have to bring the phone when you run, and yes, that defeats the purpose.
Alas.
I'll wait 'til they figure out how to decouple it from the iPhone. For the applications I'm thinking of (musical, e.g. theremin-like controller based on distance and orientation from an iPad), don't mind it being tethered to an iOS device, just sorry it has to be only the iPhone.
I will wait for it to be hacked...in 3...2...1...