Got around to watching the footage, Imagine watching this live when it's the real thing I think we'd all be glued to the screen. It was really neat to see the surface of it, I never realized it was very "planet like" with individual rocks on it, I always thought it was just a giant rock.
I still don't get how sending something relatively small dead on can actually affect the trajectory as it's like trying to stop a runaway cement truck with a gun shot, but I will assume NASA knows what they're doing. You only need to divert it slightly so guess in the end it would make a difference.