Yes, indeed. I'm not aware of any hardship when I go uphill full throttle. Going downhill is harder because I have to keep my foot in the air not to depress the gas pedal. In those cases though, I either rest my foot on the break pedal or put it down floor depending on the conditions. When the driver ahead slows down, I slow down using breaks.

I've driven for hours with and without cruise control. I've never felt any discomfort in my lower leg muscles because of using pedals.