Well, we're hung up on it because it's supposed to be good practice!
But maybe not. My first thought here was that this would be a great chance for an experiment, but then I thought, "Hey! I wonder if Marshall the Brulosopher has done this?"
And guess what? He has. It's labeled "part 1" as if there are further exbeeriments, but I could only find the one; here it is:
http://brulosophy.com/2015/11/09/cooling-the-wort-pt-1-no-chill-vs-quick-chill-exbeeriment-results/
The short version: there is a difference but both beers were deemed to be delicious. Now I'm wondering about the need, and I think I'll be doing one of these tests myself.
FWIW: for all the exbeeriments, different results may occur depending on the type of beer brewed. Would there be little difference in result with the kind of ales I prefer? I don't know, and it's a great idea to test.
FWIW, II: if cooling doesn't in fact affect the result meaningfully, then the only other reason I can think to cool fast is so as to drop the wort to a reasonable pitching temperature, so we can move on to other things.