Remove the card from your deck after the game ends
Along with that, its a pain to get rid of, because you can cast it from your graveyard as long as you remove six counters from your creatures as you do so
I also like this in Azorius Flyers with evasive aggro beaters like Judge's Familiar that you can now win with in one hit unlike the beefier Green stuff which is a faster kill
It does work very nicely in the 99 however, giving haste to newly cast creatures for just one red mana
On its own, it only taps a creature, which is weak in EDHbut once you have three artifacts (metalcraft), it becomes Swords to Plowshares without the life gain
On top of this, if youre using her as your Commander, her mono black color identity can be rather limiting