Dumb study is dumb. Where did they correlate the "distraction" with being dangerous?
Being mentally distracted doesn't necessarily mean dangerous driving conditions. Maybe missing a turn, or some such. I know when I'm on the phone driving, I don't drive dangerously but have been known to forget where I'm going!
I would assume things like eating, etc. that remove ones eyes from the road and hands from the wheel are both more common and more dangerous than being absent...
I would imagine you would still need tethering support from the carrier... In iOS 7, there's the button to set up a hotspot, but if your plan doesn't support it, it was just say to contact your carrier. I imagine the new feature just eliminates the steps of going into Settings on your iPhone, but that a supportive plan is still required.
Isn't that what Photostream was originally for? When it was first released, it was so that photos taken on your iPhone would automatically sync to your Mac, with the most recent 1,000 photos remaining on your iPhone. Clearly, more people want all photos to live in the cloud and to have access to all photos on all their devices.