The problem is they (the legislators) don't know what to do, so they do something that has no thought behind it but makes them feel good about doing something. If the problem is your hands being busy with a phone, then what about things like turn indicators, gear shifters, even simple radio controls, environmental controls, etc., etc., etc? If the problem is that your brain is engaged in the conversation on the phone instead of on the road, what about talking to your passengers, listening to a talk show on the radio, or an audiobook being read to you? And what about children in the back seat talking to you as you drive, or distracting you by banging on the back of your seat? The legislators don't know what to do, so they just make a stupid law making it illegal to "use" a phone and go home happy, having "done something" about it.
I was aircrew in a two-crew airplane. I was taught to operate the weapon system, talk on the radio/intercom, keep a watch for other aircraft and monitor the actions of the pilot, all at the same time. It's a matter of not getting too focused on one thing at the expense of all the others. It is teachable. Maybe driving schools ought to teach it and driving tests test for it?
