If you equip a skin such as the GSG-9 or Balkan addict skin, your viewmodel gets Juggernaut arms. (also includes any other skin you can equip)
The Juggernaut viewmodel has large armored arms that cover a large part of your screen. It's not a big deal, but lots of people including myself would like the juggernaut armor over your normal viewmodel removed. It'll feel less clunky, and more clean.