Aye, there is also a significant difference between hiding a many thousand ton, hundreds of meters long ship on the high seas, and a 1 meter tall human being in the forest.
Honestly I think the camouflage is more about making the soldier wearing it feel safer, as opposed to making them harder to see. That is not to say things like all-white in a winter environment, or a gilly suit are not quite effective.
Wearing only camouflage usually is not enough, but it is a basis for extremely effective concealment in the right terrain. I've personally walked one or two meters past a soldier without even suspecting anyone near. He had simply taped a few branches to his helmet and uniform and tried to kept still. They didn't cover him perfectly, but the camouflage pattern of the uniform did the rest.