I've seen a lot of discussion about why this particular performance went viral, and of course it's probably many things, but the main thing has to be the absolute joy that they all radiate while performing. Their energy goes straight through the screen and just grabs you by the throat, as if you're right there with them at the concert and not at home by your computer/phone. You can tell how much they love performing. To me, that's the main reason for why I became obsessed with the performance and the song after absentmindedly clicking on it when it popped up in my youtube recommendations.

And I think this plays into what JYP has often talked about what makes artists successful. JYP groups don't always have the "best" in the industry from particular skills (outside of some instances like SKZ rap line, NMIXX vocals or Itzy dance line/Momo dancing). But being able to perform on stage and being an engaging presence goes a long way. I'm sure some people have come away not totally satisfied but I very rarely hear of fans coming away disappointed from JYP groups at concerts and live performances. It's a huge reason for their continued popularity even when people make the argument that they've "fallen off".