Comfort and Convenience
Cabin temperature is a good example: the setting one person finds pleasant can feel stuffy or draughty to the next. Body size, clothing and seat position all change how the same airflow is experienced.
Safety and Driver Assistance
Learning where the essentials sit, among them lights, wipers, hazards and demisting, is best done while parked. Sorting that out before setting off means less improvising later, especially in an unfamiliar or borrowed car.
Multimedia and Connectivity
Phone battery is the usual weak point on a long day out. If a charging point is available, it keeps navigation running; calls and music are separate questions, depending on what the audio system supports.