ACC could be bit 'manic' on earlier mk4's which, once the road ahead is clear, tend to use near full throttle to regain any lost speed as quickly as possible. Noisy and not fuel efficient. I tended to overide this by using manual throttle to regain lost speed more gradually before allowing ACC to resume the 'donkey work' .
This has been improved and toned down on 'Facelift' cars from 2023 which now regains speed briskly enough but without revving the nuts off the engine.
I use ACC quite a lot and find it very useful, not just saving you having a foot on the 'loud' pedal. It reacts to the presence of other vehicles , and can sometimes be hesitant about t a vehicle in an adjacent lane ,and might take a few seconds before it 'decides' the road ahead is indeed clear of vehicles before regaining speed .Even though the driver may know its ok. It errs on the side of caution.
Conversely an experienced driver may sense from the behaviour of other drivers, or circumstances, that they may be about to change lane suddenly, or you may spot traffic stopping ahead before the ACC radar would detect anything happening. . So you need to work with the system, know its limitations, and treat it as a drivers aid ,not a self driving car. But ultimately ,worldwide a few crashes and and deaths may be prevented when a driver loses concentration, or is slow to react . You may drive for a lifetime and not need it,but the same could be said of a seatbelt.
