> The concern here is that you're just selling a camera that they were already going to buy.

Are you sure of that? Why would he not buy it on Amazon instead of Best Buy? Why would he choose that Sony camera instead of that Nikon ones?

Ads made him choose that model, at that price, at this specific shop. All theses variables could have changed and he would have still bought a camera, but nothing guarantee that theses variables would have been the same and Best Buy wouldn't have that sale.

Best Buy did win, because someone else didn't.

That's all considering he was already going to buy that camera and it wasn't a poor impulsive choice, which sadly happens too often in this world.