Touch screens should be legally mandated to lock out when the vehicle is in motion for all vehicles driven on public roads, full stop. Anything you need to do while moving should be accessible via controls on the steering wheel or physical buttons and knobs on the dash/shifter that are easily located with a quick glance at most.
The only thing touchscreens in cars are good for is options menus you aren't allowed to use while driving.
My car has a bunch of settings that you wouldn't be able to use without adding some kind of input device like a scroll wheel or touchscreen(or I suppose you could add 20 separate buttons).
Options like configuring how long the headlights stay on after you shut off the car, or configuring how the auto lock function works, changing the equalizer settings, etc. Touchscreen really is the best for this kind of stuff because it's what people are used to using.
You’re right, that stuff’s fine, although lots of those settings do exist in pre-touchscreen cars, and it’s just something like “press these buttons at the same time until you hear a click”