Why does the Audi A7 have a start-stop system and is it beneficial?

I've noticed that the Audi A7 has a start-stop system, but I'm not sure if it's worth using. Can you explain how it works and if it's actually beneficial?

The start-stop system in the Audi A7 is designed to reduce fuel consumption and emissions by automatically shutting off the engine when the car comes to a stop. It can be beneficial for city driving, where there are frequent stops and starts. However, it may not make much of a difference on long highway drives.