The opponent is never safe when you have haste creatures in your deck
His -2 ability gives you a lot of mana easily (if you have Koth and 5 lands on turn 5, for instance, you can play Inferno Titan and have mana open to stop Mana Leak, or hit your opponent with a 9-point Devil's Play)
On top of that, it has a feeling of Syr Konrad, the Grim, which is eternally popular in EDH
Wrath effects are a core element of casual metagames, and most often Biorhythm results in the accidental elimination of players rather than a strategic payoff
As Wizards once explained online, there is a distinct bluish, violet "pen mark" on the lower part of the card that reads "DECKMASTER," near the end of the word