I support it too, with a big + to a texting ban.
As for where to draw the line (as far as distraction) and why they chose the cell phone.
It's because that piece of technology leaves a paper trail. It's an easy, provable way to implicate the distracted driver.
We humans always ruin a good thing; it's been that way since the beginning.
There is an old saying, "Hoist with his own petard." A line from Hamlet, it's actual meaning is "cause the bomb maker to be blown up with his own bomb"
We are a strange bunch. On one hand we complain that security cameras are an invasion of privacy and that it's an example of 'Big Brother' watching.
Yet many spill their personal info, locations, vacation plans, and pictures on Facebook Ad nauseam.