What is the feature that sets Audi A7 apart from other luxury sedans?

I've been researching luxury sedans and I noticed that the Audi A7 has a unique feature advertised. What is this feature and how does it differentiate Audi A7 from its competitors?

The Audi A7's standout feature is its sleek and sporty fastback design, setting it apart from traditional sedan models. The curved roofline not only gives it a more dynamic look but also improves aerodynamics for better fuel efficiency.