I misunderstood. I agree with you that when play is in front of Giroud he usually positions himself just outside the box, fairly central, looking to be someone other players can bump balls off of. He rarely looks to find openings looking to be played in himself.
Walcott, on the other hand, wanders from side to side, constantly looking to get the ball so he can have a pop himself, or being played in behind the back 4.
However, as soon as the ball is played beyond Giroud, most often on a flank, he is almost always then getting into a position from where he can score from.