This card doesn't specify that the monsters have to be on your side of the field. As long as there is one of each type on the whole field, this card can be activated. Thus, you can Side Deck this card in the event of facing an opponent with a Deck containing many Attributes.
Decks that have easy access to all of the required elements work best with this card. "Elemental Hero," "Six Samurai," "Gladiator Beasts," "Yang Zing," and the like can benefit from having access to "Fuh-Rin-Ka-Zan" in a pinch. Note that "Elemental HEROes" also have access to "Electrum" as mentioned above, which provides all 4 elements in one.