How does the Audi A2's aluminum space frame contribute to its efficiency?

I've heard that the Audi A2 uses an aluminum space frame for its construction, but I don't understand how that makes it more efficient. Can someone explain this to me?

The use of an aluminum space frame in the Audi A2 is intentional, as aluminum is both lighter and stronger than traditional steel frames. This means the car requires less energy to move, resulting in improved fuel efficiency.

Not only does the aluminum space frame contribute to the Audi A2's efficiency, but it also provides better handling and performance due to its lighter weight and rigid structure.

In addition to saving weight and improving efficiency, the aluminum space frame also allows for more design flexibility and enhanced safety features in the Audi A2.