Topos are best in mountainous areas where you can make use of the contour lines on them to judge what is in front of you.

If the land you're on is pretty flat, a topo isn't a lot of use. You hear a lot of us talking about topos if we hike around mountainous areas. Often a topo is a bit of a combination of the topographic features (i.e. lines indicating how high up things are) and the features of a "map" too - like tree cover, trails, roads, etc.

So generally speaking, it's not magic. it's a map with elevation contours on it.