My guess is probably because of varying art styles and perhaps to add some variety to the characters (I remember White Bomber not have fingers in the anime but Mighty does). Or some characters are simply wearing mittens instead of gloves.
_________________ The Local Video Gaming Lunatic
Recent stuff I'm into:
Watching: A Certain Scientific Railgun (ep.14, stalled), Hoshi no Kirby (ep. 71, stalled), Nazo No Kanojo X (ep. 8), Acchi Kocchi (ep. 8)
Reading: nothing