Considering cycling vs walking only, I always thought this depends heavily on how steep the terrain is. So cycling is more efficient than walking on a flat road

Considering cycling vs walking only, I always thought this depends heavily on how steep the terrain is. So cycling is more efficient than walking on a flat road without headwind (which feels intuitive: give half a stroke on the pedal and you're moving several meters forward, whereas for walking you need several steps moreover you're essentially moving your complete body weight up by a couple of centimeters on every step). But uphill that's just completely different, wfor cycling having one major muscle group which needs to develop quite a lot of power. tldr; statement indeed needs some clarification.