Yeah... when I set it up, I needed to be able to run Windows natively. Hence, bootcamp. At the time, I was told that virtualization wouldn’t fly. When I set up Parallels, I just have it view the bootcamp drive.
I'm not sure why virtualization wouldn't work. It's probably just "we don't want to support it".
I've used Virtual Box for Windows desktops, Windows Servers, Linux (as many as 6 of them at a time on a laptop). It's also nice to be able to snapshot a VM and revert if I need to back out a change.