I also like this Wenger tactic, don't play a striker for most of the season(a proper striker) then bring Giroud on against Sunderland so everyone becomes convinced we don't need someone better.
In reality, this has always what Giroud has been good at, his finishing within 12 yards is up there with the best in my opinion, it's his all around game that is so lacking. You can't put him behind the defence 30 yards from goal and even hope he can make it into the box with the ball. He can't beat players, he can't run more than 5 yards with the ball.
When it comes to a CL final and you're under pressure against Barca and get one long ball on the break, Costa or Drogba might fight their way to goal, Henry could run full burn to the goal with no one able to catch him then a beautiful finish, Giroud wouldn't get 10 yards before a bad touch or being easily caught and tackled.
Anyway, battle of the **** ups wins, Arsenal often get to the top of the table(or joint top) then lose against a bottom three side.... but this Sunderland side is no standard bottom three side, this is a Derby rivalling woefully bad bottom three team which even we can't fail to beat.