I'd say that if you don't chill your wort to pitching temperature in less than 45 minutes you are asking for trouble. Wild yeast and bacteria thrive at hot but not too hot temperatures. Crashing the temperature as quickly as possible gets you out of that hot range that bacteria love, results in a better break, and allows you to pitch faster. Faster pitching gives your brewing yeast a major advantage over wild yeast and bacteria. To my way of thinking, it is one of the most important things you can do for the quality of your beer.