Trivializes some fights which are otherwise tricky to deal with, like Decimillipede in Act 2. You never really play an "Echoing Slash Deck", but you often play some sort of deck which is bad at things which Echoing Slash would help a lot with, and in those situations you should be heavily considering picking up this card if it's offered. n.b. It keeps going indefinitely. If the repeat kills another enemy, you'll get a third.
