Pixel means "picture element". These are tiny squares of color that computers use to display images. Computers have been converting visual elements into little square for a very, very long time. If you've ever seen the "jaggy" image on a page from a fax machine, you have seen a very primitive use of pixels.
The trick to making an image look the best to the human eye is to make the pixels, very tiny. That way, you just see the image, not the pixels. The screen that you are looking at has 96 pixels per inch (72 if you are on a Mac), but you shouldn't be able to see them with the bare eye.
You could, of course, invent a computer screen with even more pixels per inch. And it would be of higher quality. But no one could see the difference. So, when a product is marketed that goes beyond the ability of the human eye to detect, you are, I'm afraid, paying for snake oil.