Yeah, that’s the point. If I want to pass on a 2 lane road, I need to be pretty close to the car in front of me- substantially closer than a ‘respectful’ following distance. However, on a 2 lane road, there may be considerable traffic in the opposing lane, and passing windows may be both narrow and fleeting. And, I may need to be in ‘passing position‘ for a while before the opportunity arises. But, the adaptive crusie will see someone doing 55 in a 70 and keep my vehicle well out passing position. And and, it does it subtly so that you barely notice you are following grandma on her way to nowhere until you‘re puttering right there behind her, 300 feet back. Even the closest following distance is too far back. Adaptive cruise sucks for those intermittent slow drivers on an otherwise open road. It is ok in traffic where everyone is getting slowed down and speeds are universally variable- except that it can leave holes large enough that others are constantly merging in front of you and you keep slipping further into oblivion. It is also great on open roads where you can grab a rabbit and follow them.
I admit that I am a bit ambivalent with regard to this particular feature. I miss it when I am driving my pickup that does not have it, but curse it when I am driving the Subaru that does.