Like most Magic: The Gathering cards, the value of Jenova, Ancient Calamity // Jenova, Ancient Calamity depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Final Fantasy Art Series)
Turns out that it was pretty confusing to have a 1-word ability on a card that could do different things
Even if you have 4 dudes to tap, you only get to activate this ability once per turn, per card
Doc Aurlock, Grizzled Genius
Not all board wipes are equal though, with many either being way too expensive to reliably cast in a game or many more having weird conditions tied to them that can often give your opponents ways to keep bothersome creatures around