It doesn't really watch that way though. It was just kind of awkward. My thought process was: "Oh hey, there is Matt Smith. Wait, does he actually see him there? I wonder if we'll transition to a dramatized scene of the modern production. Oh, guess not. Huh, that was odd."
They had a lot of options for that scene. A transition through each Doctor on his own TARDIS as Hartnell looks on before finally finishing on Smith where they share that moment and it comes back to him on his own set would have been a lot more effective.