Comfort and Convenience
Cabin temperature suits people differently; one passenger feels comfortable in cool air while another finds the same setting chilly. Clothing, time of day and where someone sits relative to the vents all shape that impression.
Safety and Driver Assistance
Knowing a car's basic controls before setting off means indicators, hazard lights and demisting can be found by feel rather than by searching the dashboard. That familiarity comes from a quiet few minutes beforehand.
Multimedia and Connectivity
Taking a call on the move is a common need, and hands-free operation exists so the phone need not be held. If such a function is available, setting it up before departure saves fiddling later.