Controlling the GUI currently works touchscreen-based (mouse-style). That is, one points/clicks a element to activate it.
Automotive controls further uses knobs on the steeringwheel, an central iDrive-style hardware or gestures. They are based on sending up, down, left, right commands (cursor-style).
To make use of cursor-style devices to browse the GUI, there is the need to highlight/focus elements to visualize the position of the 'cursor'.