There are other members here who are much more expert than me, but I will say this: light pollution filters for astronomy and astrophotography have been around for a long time. They vary by price and reputation. I have used them and they can be useful if you're doing work in urban and suburban areas on fainter targets, and have a low-ish budget. However a few issues are worth bearing in mind...
Light pollution varies. It used to be easier as a lot of street lights were sodium-based, and that's a fairly narrowband type of (garish yellow-orange) light. Increasingly, it is broadband - white LEDs are taking over, which means it's much harder to selectively filter out. Second, if you're photographing stars (constellations, globular clusters, and the brighter galaxies), you don't really need an LP filter (unless, e.g. you're going for hydrogen-rich nebulae in spiral galaxies etc). Third, judging by that article, the guy was already in a fairly dark sky site. I've almost never had such rich images of the Milky Way, even in the darkest places I've been (I've never visited true dark sky sites). The before and after images looked more like a white balance adjustment had been done. I think a better example would be an urban site - and it makes me question how good this filter really is.
Ultimately, if it's something you want to pursue, you need two things: a mount that can track the sky and get long exposures, and narrowband filters for the wavelengths emitted by your subjects, e.g. hydrogen alpha for red nebulae. Some would add an astro cam or modified DSLR that has its IR filter removed. If you want to do landscape work (e.g. mountains with the Milky Way behind), there's no substitute for travelling to somewhere remote and as dark as possible.
