No, the one and only reason for it is that the build-quality of the USB port sucks. It's a bit ridiculous to say that you can save your USB port from falling out by switching batteries rather than charging the phone. I think you overestimate how many normal users even have a spare battery. At least I don't have one, but I could need one now, because the USB port has broken... Screw that, N9 all the way. The USB port on the N9 looks extremely solid by the way, it doesn't make me nervous to put some strain on it.