... it lets you compensate for a situation that might be too light or too dark.
For example, suppose you were shooting at the beach or in snow you should set your exposure compensation at +1. If you don’t your image is going to come out too dark because all those bright elements in the scene will trick your camera into thinking it’s brighter than it really is.
I do -1/2 when photographing a sunset or a sunrise when I want more saturation in the colors. When walking around I have it set at -1/3 so it reminds me that I want to expose for the highlights.
As great as the cameras are these days they are still dumb and will try to make a scene 18% gray so as photographers if we don’t want everything in the scene to be 18% you can use exposure compensation as your weapon. Our goal is to keep the colour range and tonality in the range where I want it and not where the camera wants it.