It makes more sense in the context of a world where everything is comprised on a fundamental level of a balance of the four elements. We just don't live in that world.
I do hate it when games have all these elemental stats, and then just never actually use more than 1 of them for anything. If you use 4 elemental types, there should be at least 4 different types of enemies that are weak to each respective element. C'mon.
Reminds me of the Pokemon Master in Super Smash Bros. Brawl. The three Pokemon had weakness for fire, grass and water.. But of all the other characters in the game, there are a ton of fire attacks, zero grass attacks, and maybe one or two water attacks. So it basically amounted to a debuff for Ivysaur.
This was one of the Evil Overlord list entries (or at least, an entry in one of those lists, a list like it or an addendum, etc.).
If I remember right, there it was about mirrors, and having many in the evil lair / mansion / base all turned to face the wall or covered, so that the good guys start to think the bad guy is deathly afraid of their own reflection and incorporate that into their plan to defeat evil.
Then when the good guys thrust a mirror in the bad guy's face, they can admire their own reflection and purr something like "hmm, I need a shave" before calling in the guards.