Why is quattro such an important feature in the Audi A6?

I've heard about this quattro technology that Audi has, but I'm not sure exactly what it is or how it works. Can someone explain why it's such a big deal in the Audi A6?

Quattro is an all-wheel drive system that is unique to Audi vehicles. It uses a center differential to distribute power to all four wheels, resulting in better traction and control on all types of road surfaces. This is especially important in the A6, which is designed for a luxurious and smooth driving experience.