From practical experience, I think there would be plenty of people that would agree with that notion.There are good psychological studies to show that an under-stimulated brain is an inattentive brain. Driving too slow can be a distraction causing more accidents.
I find the over-reliance of all the new drivers aids in modern cars to thoroughly bore me during a drive - my mind doesn't have enough to do and there's the potential that my attention will wander.
Drivers aids such as lane keeping assist and travel assist seem to be there to mitigate inattentive driving for those that choose to play Roblox on their mobile phones, or doing their make-up, eating a cooked breakfast etc. while driving, but in my experience, having them on and relying upon them seems to breed inattentive driving habits. I need to keep my mind busy while driving.