As I've done in the past, I will disagree with the notion that adding a UV to your system is the equivalent of proper treatment/eradication of an ectoparasite like ich. I've used them in the past - they have other potential benefits, and should help a bit when it comes to fighting ich, but they're not a total solution. They can't completely eradicate the parasite from your system.
UV units have been around the hobby for a very long time and are if they were the equivalent of treatments like hyposalinity or copper, long term aquarists and fish experts would just say "add a UV" and not advocate less convenient treatments. Also, public aquariums would just install UV units on their quarantine systems instead of bothering with other, less convenient treatments to ensure their new specimens are parasite free.