This is basically automation bias you’re describing and it’s what scares the hell out of me with these “FSD” teslas on the road.

Even if you were able to keep constantly alert during the 99% of the time where this works (which I think is close to humanly impossible) why would you want a system that doesn’t offload you at all? The only value of this system is if people ignore the limitations and allow themselves to zone out - the rest of us are at risk when it goes wrong!

I really like the automatic cruise control on my fairly new Honda Jazz. I've found that it has a net positive effect on my attention to the road, because I become less fatigued from the small, brief slowdowns that I might encounter on a motorway. There was actually an instance where I narrowly avoided a crash while using this system because of how quickly I acted when a potentially dangerous situation developed into an active crash; I felt like I was more alert than I would've otherwise been after a day of driving

However, I do not like the lane-keeping system, especially combined with the automatic cruise control. I remember testing it when I was on a clear but fairly curved section of the motorway, with my hands completely off the wheel (but hovering over the wheel, ready to take control again if necessary). I was horrified by how effectively it took me round the bend — effectively enough to be dangerous. There is a warning beep if you spend too long without your hands on the wheel at all for a while, but this was just something I did while testing it. I've not used it since, because I was confident that, unlike the automatic cruise control used on its own, this would diminish my attention and leave me unable to properly respond to an exceptional circumstances.

I own modern Kia with these systems you described. I use this almost constantly BUT: the first month after getting the car I was terrified, literally scared and 15 minutes drive exhausted me just like 2 hours in my previous car. I was learning to trust the system, had to known all the limitations first. I now know when to take over and really like adaptive cruise control especially in traffic.

I am a software engineer though, there is nothing "smart" in my home (apart from TV obviously) and I can see how people can fall into the trap you described.