The cards big downside is being a 4-mana card with 2-toughness that can be killed by almost every removal spell in the format, many of which cost one mana or are stapled to creatures, and thats a miserable feeling
We spend most of our time building up Mirri so she can attack safely and effectively every turn, piling the best equipment and other buffs on to make her a scary kitty
The card is only worth a penny though, so there's no use buying an entire starter deck for it
Voice of Victory shuts down flash, counterspells, combat tricks, and more
This ensures that you have a consistent stream of direct damage to your opponent's life total
In my youth, for example, I would have the same lunch for the entire school year