To be honest, I didn't think kids that young were capable of even playing video games. It could just be the sheer curiosity of "Why is this kid playing a car crashing game?" like, the curiosity factor of if kids are even capable of playing a game, so showing your kid playing the game adds curiosity factor.
Just remember this though, just because the click through rate and views are high, doesn't mean the video is actually performing. Look at the audience retention. I bet a lot of the views are simply curious gamers wondering why a kid is playing a video game, and if the kid is cute enough, just like watching cute puppies and kittens, there's probably the cute factor there that keeps them clicking.
I think if you got rid of "Car crash" on the thumbnail, it would elminate the curiosity factor and it would stop getting the views. I've noticed the next one has nowhere near the same views, because there's no "Car crash" in the title, meaning less curiosity, so people are probably less interested.
It's kinda like having a video of a cat playing a video game. You don't expect them to be able to play video games, so if you had a cat playing a video game in the thumbnail, it would probably get the same impact.