I think most of the issue is based with the empeg being distracting "by design". This implies potential liability issues while shifting responsibility for the action away from the driver.

Any combination of tools, devices or circumstances can distract a driver with possibly dangerous results. It does not have to be an external device - some drivers (like that example with the RAV4) are dangerous without any help. The operation of the empeg can be distracting. Talking on a cell phone can be distracting. Listening to your passenger ask "Are we there yet?" for the 100th time can be distracting, sometimes enraging.

I will agree that there are some empeg functions that are best not done while actively moving on the road. But it is a matter of judgement - the driver's or, if something goes horribly wrong, a judge's and/or jury's...