It is always good to understand how something works but it is not a requirement to take advantage of the results. The benefit of understanding is to be able to create a system model and optimize for best results without so much trial and error. I'm sure the people who are able to do that want/need to leverage their knowledge for income. I don't blame them, it takes time and money to do the experimentation and analysis work.
I know that putting dissimilar metals together is not optimum- ie. gold plated contacts are great; but the mating parts need to be gold as well. I can believe that Nickel plating doesn't sound as good. Ni and Cd have a +2 ionic charge compared to +1 for Au, Ag and Cu. This is likely more critical for IC's; but what materials and plating are typically used on powercord plugs? What plating is used on the screws and backing plates of the Electrical Outlets? These metal mismatches may have minimal impact as new; but they will corrode eventually which means local heating and voltage drops.
I have had dedicated power since 1988. I got the idea from a buddy who already was using dedicated, filtered power for years prior. I have no idea how my system would sound without dedicated power lines.
