Of course al processor manufacturers say that their processor sounds the best when used stand alone, and that can be true, it sounds the *best* standalone (in a technical way). The less steps to make in your airchain, the better the audio will pass thru. But besides that, there is also the thing of creating your own sound, your own signature. Nowadays a lot stations are using Orbans and Omnia’s, so the tools you have, are all the same. Doing pre processing is a way to get more signature to the sound. Put something in front of it, let it work and sound great together, close the door en throw away the key. Never tell anybody 🙂
Pre processing and especially this way of using pre processing is totally ignored by processor developers. I remember the Aphex 2020 witch had inserts (correct me if i’m wrong), but never seen it on other processors. I know that developers want to protect their processing quality and not want anything to be used in front of it, but a lot of people are doing it and liking it, so why not, if it sounds good (and yes, that comes down to taste)..