Heh, I would say not pointless at all given the huge number of people who didn't understand the simple physics of it. I spent an hour explaining it to a guy at the office before he finally got it.
I think Mythbusters does a great public service. All those people who thought the plane wouldn't take off may or may not have learned something about physics.. but hopefully they did learn that to question their preconceptions and require evidence about them!
P.S. Kari is hot.