Comfort and Convenience
Stepping through the on-board computer with the steering wheel buttons changes what the instrument display shows, so trip distance or consumption readings appear without the driver reaching for anything.
Safety and Driver Assistance
The driver's airbag sits in the steering wheel hub and inflates in a serious frontal impact, spreading head and chest loads across a cushion instead of the rim. It works with the belt, not in place of it.
Multimedia and Connectivity
A USB connection carries digital audio files and phone track data to the head unit, which then handles decoding and speaker output, so selection happens through the car's own controls.