Car Play in my Mazda3 works just great with the knob control. I much prefer it than the touch-only controls in my Forester. In fact I’d go so far as to say it’s the best physical option.

For example, when I’m listening to a podcast I can turn the knob to highlight the skip forward button, and leave it there. Then when adds come on I can just feel for and press the knob without looking at the screen. In the Forester I have to awkwardly hold my arm out, breaking my hand with my thumb while I try to hit the right button. Usually I don’t bother because it feels too unsafe.

You can change what the forward/back buttons on the steering wheel do, such as changing them to skip, but then I’m In the same situation when I want to go to the next podcast or skip a few.

Apple's Car Play has supported that from the beginning, since many of the first adopter cars didn't actually have touch screens, just screens.

Ah! Of all the cars I've owned (1) and rented (3+) that have it, all have had only touch screen input to it, as far as I noticed. Brb while I see if the Tune knob in my VW does anything in AA...

I'm not exactly sure how it works, but mobile OS accessibility layers provide support for "switch" devices which are used by disabled people. So I don't know if this is limited to on/off switches, or variable knobs as well, but this may be the same sort of principle that would guide a car-based OS interface with physical controls on the dash.

That's basically what Audi has (at least in some older models): it's a scroll wheel that also works as a d-pad. It works pretty well with Android Auto (no experience with Apple Car Play). Mazda also has a similar-looking interface.

But it seems those two companies are moving towards touchscreens due to market demand.