I have yet to see a UV wipe out a population of pods.
"IF" a UV is ran at the correct flow as recomended by the manufacturers then it will help.
I have a friend who owns a shop and time after time, people come in asking for ICh cures.. they try all the usual methods, garlic, Ocotzin, Oodinex etc.. and when none of this works they are sold a UV steriliser. WHen that person comes back later to say that the tank is clear the evidence speaks for itself.
Personally i keep one, its was the first thing on my list when i got my reef setup. When i have fish with such high values i like to make sure i have all bases covered. If i had an outbreak of ich and tried all other methods only to find that they failed and the fish died, i would be kicking myself if i had not also tried to save them with a UV. Granted the UV is not 100% effective, no treatment ever is. And i agree, water management and making sure the fish are kept as stress free as possible is the best way to fight this. However things can and will go wrong. When this happens i like to be sure that i have all possible options at my disposal.