That comes out to 2.5 mana per card, without accounting for the mana you spent on the sacrificed creature, which is pretty decent in the grand scheme of things
Just like all of the cards in this cycle, Enduring Tenacity, when it dies, returns to the battlefield as an enchantment, making sure that your opponent will have to kill it twice or exile it to get rid of its passive effects
With Parallel Lives or Anointed Procession, that effect becomes absolutely absurd
Pokemon TCG Pocket Microtransactions: Players can purchase card packs, cosmetics, and other items through an in-app store
Losing a Life card is never good, so opponents will be forced to Counter the attack
Each person who makes a mistake is eliminated from the game until there is one left standing