What is it about people expressing opinions about things they know little about? Do you think you are THAT smart?
The limitations you mentioned occur when using AP on city streets and indeed you cannot use AP on city streets without intervening constantly. AP is not supposed to be used on city streets anyways, so it is kinda pointless to talk about it.
On the freeway, the lane keeping and traffic aware speed keeping works really well. So much so, that you can do long distance driving with all your freeway driving using AP. You only need to take over when entering the freeway, doing the initial merges, and when exiting. If you drive at a reasonable speed (like 75 mph tops), the system can handle the gentle freeway curves. It handles cars cutting in and out, and it handles stop and go traffic (which is really nice, BTW, takes all the stress out of stop and go freeway traffic).
So, once again, the system is good enough on its intended use case that makes the driver start to trust it more and more. To the point where checking that text or fumbling for an item in the back seat seems quite safe. Unusual freeway scenarios are by definition not very common, but they can confound AP and result in an accident if the driver isn't paying attention in those few seconds.
Don't get me wrong. When AP is used as intended, driver always looking forward (and BTW, the user interface of AP actually DISCOURAGES this way of driving because the initial hold steering wheel nag is SILENT and consists of small lettering the IC display, requiring the driver to frequently glance at the IC display), then it is great - it takes significantly less brain power to the point that you arrive noticeably less tired than when driving.
It's just that the system is both too good, sucking you into trusting it more than it should be trusted, and not good enough to actually be trusted.