But feathers are an aspect of a bird, so "feathers + hurting people" is a logical extrapolation. Just like real spiders don't shoot weblines around and swing off buildings, but webshooters are a logical extrapolation of Spider-Man's power set.
And for the real trick shots, like bouncing a grenade around or throwing it so it incapacitates hostiles but only mildly inconveniences hostiles, 3D geometry would come in handy. Because if you're just dropping grenades on people, there's this thing called gravity that is just as handy.