Does cruise control require the same, more, or less focused attention from the driver than whatever it is these new features require (or will require)?
What are these features for, if they require 100% attention from the driver to monitor? At that point, why not just drive the car? Is there a goal for these features to take incrementally more and more proportion of the responsibility away from the driver, such that the driver can incrementally devote less attention to monitoring? We all know the answers to these questions. We know what the goal is here.
But the problem is, human's cannot sort of, kind of, partially pay attention to the road and the car. And any feature that propagandizes them that it will take care of incrementally more of the driving responsibility will result in less (rounded to none) attention devoted to by the driver. It's a binary proposition beyond some threshold as mutli-tasking is a myth. Do you see the problem?
As the features appear to be working better and better, the more people will devote less attention to the road even in some bounded range of their drive but this is all it takes for catastrophic errors (that will and are happening because of the nature of failure modes of AI) to occur. And these errors are qualitatively different than the ones humans make. At any given point in time the care can and will just do something completely stupid and dangerous. Swerve into a median, crash into an emergency vehicle, turn sharply into a car in another lane. There's documented occurrences of all of this. When these random catastrophic errors occur, the human will be on the margin paying less attention to the situation than if it was simple cruise control or normal driving.