Most games intentionally design the game's mechanics and the VFX in harmony so that they complement each other. FF14 is one of the rare games that doesn't seem to have put much thought into that, instead just suggesting that players who can't see through the ocean of noise turn VFX off. It's a less than elegant design choice, as evidenced by the fact that for many players disabling part of the aesthetic experience of the game makes it more playable.