Garlic isn't going to be much help if the tank conditions are crappy, no.
So some people simply won't be helped by it at their stage of the game.
I certainly have found it useful when adding a new fish to the reef however. Personally, whether ick is present or not is of no concern to me if it is not on my fish.
I keep big fish and lost that morbid fear of ick many years ago by learning to keep tanks in the best condition possible.
JMHO.