[LAU] eyes verses ears

Hi folks, Let me start out by saying that I don't intend for this to be a "which is better" discussion. This is more of a "why?" discussion, and, "what can you do with it which can't be done otherwise?" discussion. In reviewing the list of applications Gabbe used on the new album, there is mention of an application used to visualize the mix. I got to wondering. A mix is purely an auditory medium, right? So, (and I'll play dumb here) why do we need to visualize a mix? Now, part of this is purely selfish, since I happen to be blind, and so these visualization tools are not available to me. But, though I understand the advantages of an onscreen mixer, or a mouse driven interface, since, theoretically everything conveyed in an audible mix is received by the ears, shouldn't it be enough to experience it, perceive it, analyze it audibly? Now, of course, I understand that deficiencies in speakers or headphones, audio volume limitations, maybe even hearing limitations are likely some reasons for using a visual method for analyzing an audio medium, but are there others? I also understand the idea that, if a tool is available, then it should, be used, but is there something which can be achieved, in the audio spectrum, which can only be achieved via the visual medium? Just some thoughts. Rusty