In addition, if your Squirrel deck is monogreen there's no reason to avoid artifacts
Mythic packs are worth 260 gems or 1,300 gold, whereas regular packs are worth 200 gems each at about $1 for 200 gems, meaning 50 packs equals just over $50 worth of stuff
Meaning that the regular Discard Filler will be probably one of the most common filler in existence (As it comes from 7 different sets since 2012)
I also appreciate the flexibility: Assuming you can gain life on demand, you always have the choice between giving the board -2/-2, which potentially salvages your board while it removes key threats, or blowing up everything
The turns when you get to discard it and another 2- or 3-drop, cast this card for its mayhem cost, and put another creature into play will be very strong, indeed