When thinking terms of what the body naturally does, its fine to do direct arm work, to say otherwise, isn't correct. In addition, the arms (when performing compounds) are responsible for engaging the larger upper muscle groups, and sometimes the arms can be the weak-link, not allowing pre-mature exhaustion of the larger muscle groups, and therefore, doing some (reasonable) direct arm work to remedy this compliction, is good dependent on the individual person.
29 years (4/26)
Height: 5ft 7in
After losing 40ish unwanted lbs: