Navigation:
The cognitive load is very high on both vehicles. Using dials and buttons on my Audi is really hard and the maps are loaded with random icons and its a bit harder to parse where I'm supposed to turn next.
The voice directions work really well on the Model 3 since I assume it just pipes it to Google Maps. My Audi is terrible unless it is "home" or something obvious it wont misunderstand.
AC/Heat:
I have to look down for both cars. In my Audi, the physical buttons for the fan have digital displays for the speed and temp. So I have to look and read anyway.
Music:
There are next/previous and volume buttons on the wheel in the Model 3. No different than my Audi. Tapping the giant screen is definitely easier than tapping on my tiny iPhone screen like I currently do in my Audi.
That sounds awesome! It means I can do something without having to look away from the road. I don't have to actively context-switch whatever I'm thinking about to navigate on a touch panel. Whatever these guys are doing, it sounds so much better than dealing with glare and non-responsivity issues.