Yup, I've used a paddle shifter in a rental for this very purpose--using the engine as a brake while going downhill. My Corolla only has two possible downshift

Yup, I've used a paddle shifter in a rental for this very purpose--using the engine as a brake while going downhill. My Corolla only has two possible downshifts and neither is all that good for holding speed on a downhill but the cruise control is integrated into the system--I can set a speed and the computer will do a pretty good job of using the engine to keep from exceeding it too much and since it's adaptive it will always avoid the car in front even if otherwise it doesn't hold the speed that perfectly. Since I found that out I've never touched the downshifts.