I agree that rarity draws are the best for most players. It might not be the case for the people with tons of staked SPS, maxed level decks, and in the upper leagues. I think the energy from chests might pay off for the investment. However, that isn't the case for me and I prefer rarity draws. I think the numbers make sense and we got loot chests for advancing leagues, so I think you will probably need slightly less.