I remarked to my wife showing me a video recently that you could tell it was taken on an iPhone, I don't think it's just the 'punchiness', for me the main thing is the way it seems to attempt to smooth out motion - the 'in' thing seems to be to sort of spin around showing what's around you while selfie-vlogging and tik-tokking and what-notting, and iPhones make it look like you did it with a steadicam rig that's not quite keeping up.