First, consider how many top-level IPSC shooters you will face on the street if, God forbid, you should ever have to draw your weapon. I would say you have a better chance of winning the lottery and being struck by lightning in the same hour.
Also, good points have been made about the way things go when bullets are being launched from both directions instead of just one. Another good point that IPSC is a game, it is not fighting. It's easy to hit a stationary target (even a moving one) when you know it will not be shooting back, when you know where it is or where it will come from, and when you have either walked the stage over or watched other people shoot it.
pointfiveoh made a good point - draw and shoot as you move to cover. In short, get out of the way while making the other guy's life difficult.
IPSC shooters are skilled, no doubt about it. They are excellent at what they do. But, so are the people who throw knives at the circus, and I wouldn't ask them on how to defend my life with a knife.
The pen is mightier than the sword - unless you are facing a man armed with a sword, then the pen is pretty much useless. 45 Fu