The point is that throwing can hit as hard as a lot of Xbows, can be held like an Xbow, and can fire faster than a bow. The two downsides, low ammo count and inaccuracy can't really be exploited by an opponent in a skillful manner in the same way the downsides of Xbows (Very long reload times) and Bows (Have to fire as soon as the bow is drawn) can. It's just luck, and that really sucks.