Why does the Audi A8 come with a mild-hybrid engine?

I have been considering buying an Audi A8, but I am not sure about the mild-hybrid engine option. Can you tell me the benefits and drawbacks of this technology?

The mild-hybrid engine in the Audi A8 not only reduces fuel consumption, but also lowers emissions and provides a smoother driving experience. However, it does come at a higher cost.

I have the mild-hybrid engine in my Audi A8 and I highly recommend it. It not only saves on fuel costs, but also adds a level of sophistication to the driving experience.

The mild-hybrid engine in the Audi A8 may seem like a small feature, but it has a big impact. It not only improves fuel efficiency, but also enhances the car's performance and handling.