Comfort and Convenience
Seating position is a personal matter: height, leg length and driving habits all change where someone wants to sit. Two drivers sharing one car often settle on noticeably different compromises between a clear view and relaxed arms.
Safety and Driver Assistance
Spending a moment before setting off — mirrors, seatbelt, demister, hazard lights — means those things have already been found once traffic starts. Preparation while stationary is simply easier than hunting for a switch on the move.
Multimedia and Connectivity
Keeping a phone charged is a need in its own right, since navigation draws steadily over a long day of stops. Where a car provides a power source, the practical value is arriving with the phone still usable.