Hi Thomas-
To respond to this:
It always puzzles me when someone asks this question 
The short answer is, just because I like it that way. The technical question; however, is that I have a few sets of speakers. I switch between these speakers to give different colors (that I like) to my ears during mixing. I have a set of NS10m’s, a set of KRK ST 8’s, and a set of Avantone (“horror tone” knock-off’s). I will routinely switch between these sets to give my ears a fresh perspective on the mix during a long mixing session.
One of the benefits of the switching in Control Room is that I can setup each set as I like, including plugins. This is particularly good for me because, since I don’t have a room built for my studio (yet,) I don’t have a tuned room and I use IK Multimedia, ARC2. I have a different setting for each set of speakers. In the Control Room of Cubase I can set the plugin with the settings for each respective speaker set.
While WaveLab 9.5 provides for SOME of this functionality today, what is does provide for is, at best, inconsistent. I’ll setup a set of speakers the way I like them, but when I launch WaveLab in a later session, the settings are not there, or are not functioning as I left them.
The Control Room in Cubase is a much better speaker management system than what exists in WaveLab today. Hopefully we can get the same Control Room on WaveLab one day
Sorry it took so long to respond. I’m not in here all the time . . .