How does the Audi A4's Smart Key function work?

I'm curious about the technology behind the Audi A4's Smart Key. Can someone explain how it works and any potential benefits or drawbacks?

The Smart Key technology in the Audi A4 essentially allows the car to recognize when the key is in close proximity and unlock the doors automatically. A helpful tip is to keep the key in your pocket or bag while approaching the car for a smoother unlocking experience.

Aside from the convenience of hands-free unlocking, the Smart Key also works as a safety feature. It will only unlock the driver's side door while all other doors remain locked, ensuring the safety of the driver inside the car.