Not sure that it is always as simple as that. I know quite a few people who are terrified of using a cruise control, and that includes a few senior family members. It is that feeling of the pedal pulling away from your foot, which terrifies them.
If people are made aware of what affect using a cruise control has, what they feel, how the vehicle reacts, etc. then they can learn to use it. But just saying it's easy, or just switch it on, without giving further information is not helpful to some people.
Lifey