I thought we already agreed your grand kids are awesome.
Seriously, though, I don't believe many 7 year olds can do what the kid did in the video. I also think his movements were as crisp and controlled as in the other video. He just was trained to do different things. And, most importantly, exceptional kids may invite comparison to one another, but I don't see much good comparing them to an average kid. For most kids, teaching then there is value in an activity even if you're not elite is a great life lesson.