I'm a little surprised by the number of people I've seen all over (online and off) questioning the video selfie. Ugh, I just shuddered using 'selfie', such a dumb term. Anyhow, maybe I'm in the minority but I often take video of things to later pull a single frame out of it depending on what I'm trying to capture. It's easier to flip over to video mode than it is to switch the settings to "sports mode" where it will snap like a thousand pictures a second to try to be sure to capture the moment.
So if I was dumb enough to do what this kid is doing, I would also take video and then scrub through it looking for a single great frame to use as the actual picture.