Why do Pickleballs have holes

Some people asked why do pickleballs have holes?  Here's the reason why from USAPA newsletter:
Sound Off… Reader Feedback
I would like to respond to the question from Ed Mandler, Saddlebrooke Pickleball Association, about using a no-hole ball. They are available from one of the pickleball vendors and one of our players bought a dozen. I have played a couple of games with one of the no-hole balls and it is no fun. My main complaint is that it doesn't travel in a true line. It travels much like a knuckleball in baseball. Sometimes it will sail upward and other times downward and other times sideways. It seems to be heavier than the regular balls and when it hits you it hurts. It was fun to try, but it is a waste of time to play with on a regular basis. John Bliffen, Troy, Ohio