Question.. Eating exercise calories?????

Ok, so when we exercies we get "extra" calories on that day. I read some post saying you're supoosed to eat those calories, but I'm not understanding why. If I burned more calories that I ate, then that is adding to my weight loss, right? Isn't it the point to eat fewer calories than what we burned? If you eat your exercise calories, doesn't that sort-of defeat the point?

Help!