Rainbow life has the benefit of working against all enemy attacks on one turn, which can be pertinent if your board is empty. Though, that does mean the optimal time to use this card is when you are behind in board state and the cost of discarding a card is heavier. Draining shield has more consistent use in all stages of a duel and can activate aromages effects (like rosemary).
Basically, you can't get it anymore for now.
I myself didn't have particularly good luck with drops and only scored 1 of these cards, while at the same time I got TONS of other (useless) cards, including UR/SR I will never ever use.
Anonymous
Anonymous No. 2
