Pseudo-science regarding health, especially pain-relief is especially egregious, as it preys on the desperate. It's why I'm such a hard-ass with this shit. Woo regarding "pain relief" has had a surge of success (well, attempts) recently given the so-called opioid crisis in the US and anything thats electrical, is a marketers dreams because it means they can bring lots of numbers in on the advertising (numbers don't lie... right?). Microprocessor controlled, using deep learning, machine learning, and quantum tunneling.. etc..
Add to the mix things like "natural" (like everything in the universe) and "side effect free" (which is impossible) along with a not-too-high-a-price and people will buy it and think "well, I'll give it a try.. why not?". It is why these product will always exist. There will always be a market of those in chronic pain, willing to suspend believe if the product looks swanky enough, and we can't really blame them. We can however blame those who fail to show any form of efficacy by performing trash trials.