The level is thereto ensure that you are not canting the bow.

I don't like them for hunting. They take my focus away from the deer. I would rather use the time I would spend "leveling" the bow on judging the distance to the target.

With proper form you shouldn't need one for hunting. Some guys like them as a measure to double check ones form.

Like most things on the market, they are worth a try. Everyone is different. Best of Luck.