I think all distractions should be punishable if you inflict harm. The reason you hit someone other than life threatening injuries or unavoidable accident are meaningless IMO. You did something you shouldn't have and should deal with the consequences.
I also don't think it's fair to equate reaching for a cassette to texting. One takes up a few seconds unless it falls on the ground (at which point you should be charged if you're dumb enough to reach for it) and the other takes up several seconds of distraction to look down at a screen to read or enter a reply. If it's important enough to communicate while driving, dial a number.