The trouble with analysers is that they tell you how much there is at every frequency, but not how nice that content is. Ears can be trained and when they are, they are infinitely better than the visual display. As part of what I do I have lots of radio test gear - exactly the same thing exists there - spectrum analysers that look at radio frequencies. I can see exactly what is happening but exactly like audio, while seeing it helps me work out what is happening - it won't tell me how far it will travel or sound like the other end. A bit like how you can tune your guitar with a tuner more accurately than anyone's ear, yet the damn thing sounds out of tune on some chords at certain positions.