The 120 pendulum thing was an idea life had early in the war. While an off element pillar is a dead card in 11/12 decks, a life pendulum is useful in all duo decks AND in mono. As such, we chose to fuel all our decks with pendulums. Now, from last war, I had learned that you always need more pendulums than you think you do. Because we had an excess of pendulums, we could discard pendulums early and then convert to get them back, effectively allowing us to discard any card in our vault, instead of being stuck with in deck cards.
This strategy worked extremely well.