What is the difference between Audi A8's Traffic Jam Assist and Adaptive Cruise Control?

I'm considering buying an Audi A8 and I'm confused about the differences between Traffic Jam Assist and Adaptive Cruise Control. Both seem similar in helping with traffic, but what sets them apart?

Traffic Jam Assist is an expansion of Adaptive Cruise Control and adds the ability for the car to actively steer and keep the car centered in its lane.

While Adaptive Cruise Control only works at speeds up to 130 km/h, Traffic Jam Assist can also operate at lower speeds, making it more useful in congested city traffic.

One major difference is that Traffic Jam Assist uses both a camera and radar sensor to monitor the environment, while Adaptive Cruise Control only uses radar.