In their defense, when it is needed, more power is better, and when it is not needed, it makes no difference to the sound, so consequently it does no harm to the sound. But buying more power than you ever need generally involves wasting your money, and making them richer. They get richer whether you need the power or not, so for them, it is always good to get people to buy more power.
Fortunately, one way to make more money is to make a better product that some people will appreciate. Unfortunately, another way to make more money is to con people into believing that one has created a magical device that makes everything good. Some companies primarily operate with one of those methods, others primarily operate with the other method, and still others use both methods (though not necessarily simultaneously).
If you don't like being a sucker, then it is a good idea to examine the various claims made, including those of people with whom one does not agree. Of course, some people are suckers their whole lives and never realize it, so they never are vexed with having been fooled. They simply waste money and effort on things that do not help, without ever realizing that that is what is happening. Smarter people, however, catch on to such things after a while (the smarter the sooner, but better late than never, and certainly smarter late than never).
Anything with a price tag on it is about money, no matter what the manufacturer or salesperson may claim. Their job is to get you to part with your money, regardless of whether you will get a real benefit or not. The more money you part with, the better they are doing their job. It makes no difference to this fact whether you part with your money for something that actually does something or not.
