Comfort and Convenience
A multifunction steering wheel duplicates selected functions on the rim, so a driver can step audio volume or cycle on-board computer readouts without releasing the wheel, while the underlying system itself is still switched on from its own panel.
Safety and Driver Assistance
A lane departure warning system reads lane markings through a camera and alerts the driver when the car drifts across one; signalling first tells it the move is intentional, so the warning is suppressed for that manoeuvre.
Multimedia and Connectivity
A 12V outlet only supplies current, powering a charger or accessory, whereas Bluetooth carries no power at all and instead handles the data link that sends calls and audio to the sound system.