Well. if you call that "pretty stiff" you might want to get out to the gym or something, because the pipe cleaner is super soft.  Maybe they would be an ok pipe ski for someone extremely light, but that's about it.
And at the X-Games, Tanner's equipment manager Dano had 5 or 6 different pairs of skis at the top of the pipe for Tanner, all with custom flexes, so the point is, what Tanner uses in the pipe are NOT the pipe cleaners that the average person can buy, not even close.