A hooded sweatshirt has many uses.
It keeps you warm.
It breaks up the outline of protective vests and web gear.
It can be easily layered. A pair are even better — combine a medium-weight and a thin lightweight, preferably in a different color and/or pattern, and you’ve got versatility in weather endurance. Oh, and they have other uses as well.
Truly a good thing to toss in the kit.