It is because of the proliferation of photos and videos like this that people get the idea that the crap on their walls actually does anything.
That's why I go on and on about not copying the work done in videos and photos. It's the blind leading the blind. Artists are unique - strange birds, some of them.. (no offense to you guys..) and they will go about to re-invent the wheel. Some refuse to do any research or check facts because they mystically believe that they might be on to some magic.
Acoustics can be done artistically but one must first follow the principles of physics that control it and define its behavior.
You can put egg crates on your wall if you want to... then again - you can crap in one hand and wish in the other and see which one gets full...