It's just that spending enough time in this forum, I have heard people say that:
"This [CD player, DAC, Preamp, Amplifier, Cable, Sound Treatment, etc.] made more than a subtle difference in my system, improving the [bass, midrange, treble, clarity, soundstage, imaging, etc.]".
And that's just a single component. Change all the components and add the variability of the rooms, people in them, speaker placement and the demo music being played, and I would surely have a difficult time making any comparisons.
But I could certainly come away with general impressions. Room A system sounded extremely full and dynamic. Room B system had a definite lack of bass and tonal coherence.
I agree with Nuance. You get to see the new equipment, get a real close look at the fit and finish, talk to designers and industry insiders and meet some new audio friends.
Then......hopefully come away with an idea of what components you might like to try and audition and compare at another time and place. And if you're very fortunate, your own listening room!