It depends upon how much study one does: (NOTE: this was a driving stunt, solo, over a two week period in July 2013.) I reach cruise control speed with traffic and thereafter, don't touch the accelerator. Bob Wilson
I'd not say "floor it," because that's really overkill, but you should feel that surge of forward momentum and the speedo click upwards at a respectable pace. I'd use accelerating onto a busy interstate/freeway as your guide. Having to get from 35-40 to 60-65 in a few seconds = hard acceleration. The only way you can slowly accelerate and do better is if you are on a level surface or decline and can exploit gravity/traction motor to do the job. Any kind of incline pretty much mandates kicking in the ICE, and at that point you might as well apply the gas about halfway or more into the PWR band to get to your desired speed ASAP.
CC is decent, but when there are quick load fluctuations due to hilly terrain you can do better with your foot maintaining constant load rather than CC's constant speed, and of course when the load is low, induce a pure glide or electric assisted glide.
The experts agree that the optimum ICE efficiency is in the upper half of ECO. The CC can take you into POWER. So I wouldn't look to the CC to learn FE lessons, it just tries to maintain speed. Going over small hills, you want to avoid regen, it's better to gain a little momentum (eg from 50 mph to 55) that can extend your glides. That's because regen is said to be 30% efficient! and the increase from 50 to 55 doesn't eat that much energy via aero drag.