States are likely to have laws against “distracted driving” or “reckless driving”. Those likely encompass much of the driving while texting or fiddling with controls. Unless a cop directly saw the action this are usually charges levied after an accident happens and do nothing to prevent it. Once enough crashes are attributed to a narrower set of actions, public opinion can be swayed to support action against that narrower set. Now with a specific “no texting while driving” law, cops can pull you over simply for holding a phone. They don’t need to see you do something that would constitute “distracted” or “reckless” driving to ticket you.