I don't know where you get the idea. Even plane autopilot will not land the plane w/o Pilot's supervision.
People who don't read manuals put themselves at risk.
Even simple systems like Cruise Control carry plenty of warnings that one should be familiar with when operating (from Ford's manual):
WARNING: Always pay close attention to changing road conditions when using adaptive cruise control. The system does not replace attentive driving. Failing to pay attention to the road may result in a crash, serious injury or death.
WARNING: Adaptive cruise control may not detect stationary or slow moving vehicles below 6 mph (10 km/h).
WARNING: Do not use adaptive cruise control on winding roads, in heavy traffic or when the road surface is slippery. This could result in loss of vehicle control, serious injury or death.
[and few more, shortened for brevity]