I don't deny that cruise control has some advantages. I just suspect that using cruise control tends to cause people to think less about the rest of their driving. It makes people lazy.

The few times I have had a rental car with cruise control I have noticed that I drive worse (don't pay as much attention, make worse judgements of risk) if I use cruise control for a prolonged period.

My experience of US freeways is scary. There seem to be so many single car accidents, where people look like they just drove off the road.