Having those apps run on the main screen has advantages...
- touchscreen is easier to access
- screen is bigger
- screen is better placed (less eye movement = safer)
For media apps at least, they can be controlled fine from the buttons to the steering wheel, no need to take your eyes off the road. Any navigation app you're going to have to look over anyways. I've used Waze in a Tesla, didn't take me any more time to look at that than the map on the upper screen.
The steering wheel is going to control an app running natively in the phone (which is sitting in a cradle, and not linked by CP/AA)? That's what the post above mine was asserting worked well.