A friend and I have now completed all 15 standard scenarios, I've played a further 6 with somebody else and I've worked through the 2nd Rolica scenario solo 7-8 times.
We have found that this card swings the course of the entire battle whenever it is played unless the dice produce a crazy result. A carefully orchestrated assault, building up a hand of cards and positioning units, hits a brick wall all because of one card. Inversely if you have this card when you launch the attack then you're really likely to smash the opponent.
It seems to me that all the cards have been ported over from other editions of the rules, CCA, M44 etc rather than tailored to the new game. Some just don't fit or aren't balanced.
At the other end of the scale, Give them Cold Steel has only ever been discarded, I think perhaps it's been used once in all the games. In fact if we took it out we'd only miss it because it wouldn't be glogging up our hands.