It does make a difference
As a cop in Scotland, I can safely say that having followed a vehicle having identified the driver as using a mobile phone, the vehicle moved erratically and moved across the entire breadth of the lane which it occupied. The offside tires at one point crossed over onto the oncoming traffic. The driver when stopped admitted to using his phone both for a voicecall and then to text. In the days of touchscreen phones, you now have to look at the phone instead of using the physical buttons to text. Even glancing back at the road, how many times do you have to look at your screen?
This is one example from dozens of cars I've stopped for using a phone and I'm not even a traffic cop.
Now I'm sorry, but you can give me all your academical studies in existence. Using ANY form of device which distracts you from the road is dangerous.
Realistically, if your eyes come off the road for a second regardless whether it's to check your phone, your Satnav, your radio, shout at the kids, then you are covering a large area of ground at speed without awareness of what's going on in front of you.
Also, here's an interesting bit of info:
Legal definitions in Scotland: A person is held to be driving a vehicle when he or she has control of the direction and speed of the vehicle.
Stated cases support this, but even if you are pulled in at the side of the road, as long as you are sat in the drivers seat, you have that control and are held to be driving and are thus eligible for a Fixed Penalty Notice (£100 and 3 points) for using a phone.
Not that it would ever be enforced mind you, but in the eyes of the law it can be. Same as the guy who was charged with being drunk in charge of a vehicle for being asleep on the back seat even though he'd put his keys on top of his back offside tire. :|