A great damage tool for Tundra Orcs. Converting many of your commons into much more valuable units. You should probably use both of this event in every game, often just attacking with 2 commons is more than enough to justify its use.  Its drawback can even work in your favor as a friendly unit that destroys itself with this card prevents your opponent from harvesting the magic.
Making your Frost Shamans have 5 attack strength and Smashers have 6 can make short work of enemy champions, gates, high life commons and even maybe their summoner.

This is also why it's important to always have a few Frost Shamans around, to make use of For Glory when the time is right. A damaged Frost Shaman is the best use of For Glory. Obviously you want to have an Influence boost also ready when a Smasher attacks with this event as even to deal 6 damage, killing your Smasher in return is not a great trade.