When discussing the 3-2, everyone seems to point to its obvious use of defending 3-point shooting.

But is that advantage exclusive to 3-point shooting only, or does it also work well against opposing guards who still take a lot of shots even if the majority of those shots aren't treys?

I've been running a 3-2 with one of my teams for a couple seasons now, and though I can't give you any concrete numbers to give you a proper confirmation I do feel it is effective at doing what you're aking. I typically play at a -2 (sometimes -3) so I can defend both perimeter and mid-range attempts, or at least this is what I'm trying to do in theory.  

My gut feeling is that this actually works better than I initially would have given it credit for WRT reality.  If a team has guards with virtually no perimeter, a little low post, and a ton of ball-handling, they're more likely to drive to the bucket and the 3-2 hasn't worked as well for me against those teams as the 2-3.  If they have sorta mid-40s-ish perimeter they tend to behave a bit more like mid-range jumpshooters and the 3-2 works pretty well.  Of course, I only play the 3-2 very rarely, so my sample sizes are painfully small and could be entirely coincidental.

Of course with billyg's suggestion that players are rated basically on "offensive skill" then I would imagine inside the 3 point line a guard might just be a guard, in which case what I suggested above is entirely implausible.