The only bad part of it is that it attracts attention. The UAV can be a VERY powerful tool for spotting, keep it far enough away that to the casual eye it's just a dot on the horizon, and spot everything in sight. Your team will love you for it, as tons of red triangles popping up all over the place give them outstanding battlefield awareness.
the only time a uav is suppose to go offensive is when it seens a tank or is bombing the objective. you are attracting attention if you are using machine gun and it will get killed fast. ram uav into choppers