There's a tremendous difference between chatting with a passenger and having a conversation on the phone (whether you use hands-free or not). The passenger will notice when things are happening around the vehicle and the conversation will quiet down and then resume once it's safe to do so. The person you're talking to the phone doesn't do that. And as others mentioned in other posts, children are just as much of a traffic hazard as cell phones in this regard, but most are willing to accept that it's a necessary risk. Phones, less so.