There's no doubt that watching volume levels with your audio- and video-centric projects is important. The digital audio world has a top limit --- 0 dBFS --- that you can't exceed. But screen real estate is often at a premium when working in the Vegas NLE. Sure you can pop the Audio Mixer and/or Mixing Console over to a secondary monitor, but that's often filled up with audio/video effects, waveform/vectorscope monitor, and even full-screen previews.