Frankly, it is a sad state of affairs. Just look at your e mail box in the morning. One scam after another. Most people do not have an extended scientific background thus are open to believing stuff that a person with the right learning would laugh at. None of us can know everything.
Audiophiles are easy targets because of the manner in which we perceive sound which is extraordinarily complex and open to interpretation by that thing sitting in between our ears. I'm afraid there are an unlimited number of scam artists willing to take advantage of this.
Go here
https://www.thecableco.com/ and check out the accessories section. What party of garbage. My favorite is the Bybee Quantum Clarifier. Dig this. A 2" square chunk of wood that you attach to the back of all your drivers right to the magnet. $100 dollars each. That would be $600 for your average three way speaker system. Buyer be ware is the old adage. If you make the choice to buy something it is not theft even if the item is severely miss represented. There is not one item on those 5 pages I would even be remotely interested in. This does not mean that there are not some great products out there but the vast majority of "accessory" items would fit better in the category of "garbage." So, from a statistical perspective you are more likely to buy junk than a useful item.
My own approach to this problem is to stay away entirely. I would much rather buy music.