Comfort and Convenience
Preferred interior temperature varies from person to person, so a climate setting that feels pleasant to one occupant may leave another reaching for a window.
Safety and Driver Assistance
Practicing how to adjust mirrors and operate turn signals in a parked car builds familiarity, making it easier to focus on traffic when actually driving.
Multimedia and Connectivity
Listening to music while driving helps pass the time, but without a confirmed audio input method, a phone's library cannot be assumed to play through the car's speakers.