Why does the Audi A7 have a fastback design?

I was curious why Audi decided to give the A7 a fastback design instead of the traditional sedan shape. Does it serve any specific purpose or is it purely aesthetic?

The fastback design of the Audi A7 actually serves a functional purpose. It helps improve the car's aerodynamics and increases fuel efficiency.

Aside from the practical benefits, the fastback design also gives the Audi A7 a more unique and sleek look. It sets it apart from other sedans on the market.