Isn't it really just fashionable at the moment? Saying 'it just works' is a bit like saying 'Hush Puppies will always be cool' in the 90s.
I'm already getting tired of bootstrap sites to be honest. I think it's going to end up backfiring on twitter in that their design will look very generic and boring because everyone's using bootstrap.
His original video is here: http://www.youtube.com/watch?v=l-ZgtOZJVKE
Edit: sorry, didn't get the part about the "Hero + 3 below". Care to explain?