See, because you hit the reply button in my post, I can clearly see that you were replying to me. If you replied using Cody's reply button, then I would have to either assume you were questioning Cody about the many things he brought to mind, or you were asking me. Nonetheless, I'd have to do inferring...
We have that reply button there so it can activate the quick reply box and vBulletin will know what post you are actually replying to. This can enable it to automatically quote the post and will allow Hybrid/Threaded Mode users to easily see what's what.
If you don't do that, nothing bad will happen. We just won't be taking advantage of the software. Nothing will change. Posts will keep getting piled into one another in an unorganized fashion and vBulletin will want to murder us all... (well, maybe not that last part).
Anyway, I'm just asking all of us to try this. Let's take advantage of this great software!