So true. But you lose on real-time mixing decisions. Actually, Audition is somewhat real-time; what I don't like about it is how it doesn't reflect automation properly. I've had discussions with some folks in other (non philmusic) forums about Audition's automation features and for me, it fails the vst automation test - try to rt-click on a clip and try to assign any vst parameter to be automated.
BAMF, it's different when you twist the knob and hear the effects kaagad, you easily make mixing decisions without having to go back endlessly saying "what if I made the reverb -1db lighter..." or something like that - positive feedback, ika nga. It's a real time saver, and one of the reasons why I chose Cubase. This is not a plug for Steinberg - I have both Sonar and Cubase and I can compare both; I personally like mixing audio in Cubase more than in Sonar. I've used Audition/Cool Edit in the past in other studios, it's quick for banging together a track. But if you want mixing flexiblity, it's Cubase/Nuendo first, Sonar 2nd (Pro Tools would probably be first but I can't afford neither software nor hardware).