I think the theory is that the power cable creates a magnetic field around it that could interfere with the ultra precise electronics and what we are looking at is shielding for it. It could be complete bullsh but there is scientific reasoning behind it. It's for people who pay premium to reach that final 5% and I have some weird kind of respect for such passion. When you are paying north of tens of thousands of dollars for a system, the expensive cable is the least of your problems.
That can't be said for people who pay several thousand dollars for a premium hdmi cable that is supposed to 4k-ify a full hd signal. That what constitutes as snake oil in my mind.
You have no idea about business expenses do you. I work in the events industry, corporations hold single evening events for their higher up employees for 10s of thousands in only technical expenses, before the venue asks for rent, or the catering etc. A single month of any basic service on the enterprise level starts from 5 grand.