I think there are some semantic issues in the video presentation.
The title is Art Vs Science, but the video mainly seemed to talk about listening vs measurement. I get the connection between measurement and science, but categorizing listening as art (or science) gets very sketchy.
We are enjoying art when we listen but I can make an easy argument that listening is as scientific as it is artistic (but I would not really even want to view it in those terms)!
The second area is the treatment of "blind" as in blind testing. I appreciate that you point out that a better looking product does make a valid difference. However, if you understood the role of blind or double-blind (which often do not even involve something you can see) experimentation, you would recognize that the reason for testing blind is not to eliminate the bias of visual appeal, but to eliminate the bias associated with an expected outcome. An obvious example is a placebo drug test. If everyone knows they are taking the placebo, the experiment is invalid.
In terms of audio, an poignant example might be to see if listeners can hear a difference between a BlueJeans Cable and an AudioQuest Cable. If you let the average person know which is which and let them know the cost during the experiment, the AudioQuest will be statistically preferred. That is why you test blind!
Personally, I have read (and believe) that my Paradigm S-2 sound better with the grill in place. However, I will never put the grills on because they will always be "better" speakers in my experience when I can see the drivers! So I understand your point, but even in that context, I think there is value in knowing that I am choosing looks over (a minimal improvement in) SQ!