They’re not essential in anyway, but I love the what they add to the game. If I’m being completely honest, I don’t run into many double failures during a game. It’s even rarer than a double success, and we all know we don’t see them that often.
So it doesn’t break them game by making it too easy. What it does is add an extra layer and dimension to your decision making. For example, if you’re rolling three dice and get two blanks and a partial success, there are some benefits to collecting the two tears instead of discarding two action cards.
For what it’s worth,, I think this box is totally worth it.