Why does the Audi A8 have a dual-density foam in the seats?

I noticed that the Audi A8 has a dual-density foam in the seats. What is the benefit of this and how does it differ from other types of foam?

The dual-density foam in the seats of the Audi A8 provides increased comfort by adapting to your body's shape and weight distribution. This foam is also more durable than other types of foam, so it will maintain its shape and support for longer without needing to be replaced.