OK, this was painful to watch. Not too elegant to argue with someone not present but since it's a public video here's my $0.02:
After the funny snake oil intro the guy doesn't support his point with any data at all. He keeps repeating how pissed he is, his opinion on that ******** USB cable, he is cussing but he doesn't say anything substantial to prove it.
Error checking. Perhaps he should be noted at this point that it is error checking _without_ error correction. USB audio is not how the printer works. He should know this if he really has a background in computer networking as he claims.
IUT Audio purifier cable: after all the tests of the cable he provides no details about test methods and presents no measurements. No proof, we just have to take his word. Typical.
RCA cable: “At least it got power it can do something.” Wow dude, is this your reasoning?
Nothing but cheap talk for 18 minutes in a video that was recorded with a head camera that makes me dizzy watching.
It's also worth to mention that the difference between USB cables is smaller than his $1,500 setup could easily reveal.