It has been an annoying thing that you have not much surrounding perception except audio, and it is especially dangerous when you are driving or flying.
Also the stuff unloads when you go into the map, so it takes a few seconds to get out of the map. When you are in the heat of battle, that a few seconds counts.
Having a PIP screen in the map view means that you have at least some type of visual surrounding perception and can avoid a lot of accidents.