It would probably do considerable damage if people decided to hug him when he was exploding. But there likely aren't too many stupid enough around for that. For these hunters, a second is a long time to put some distance between themselves and Youpi. If they couldn't survive an explosion of that scale without any fragments from a distance, they would have no business invading the King's castle and fighting royal guards. They might not be as absurdly resilient as Youpi and Pitou, but they are still tough guys with their nen mastery.
It's nice Gon just continued sitting without a reaction, that murderous expression on his face, not giving a shit about Pouf approaching. That's how badass he is these days. Like a pro.