The hit rate isn't good enough and you can just come up against a deck with painfully few good targets
Summary Combo decks always fire cantrips on Turn 1
As if there was any doubt, Mishra immediately tells us we are an artifact deck
On the one hand, it was face down when it left the battlefield, and thus had no abilities
So that was the thing that originally we did not plan to put that art on a playmat, but it was just so good, and it's just one of those things I love about this game is that the art every time there's these, you know, all art is amazing
Then to top it all off, the Sparkhunter also has Protection from planeswalkers, thereby nullifying their ability to retaliate directly using their own abilities