Its typing also matters
If a player would draw their second card in a turn, you get to draw as well, and then if a player casts a second spell, you make a 2/2 Knight token
Otherwise you'll suffer the indignity of getting pecked to death by tiny birds as you sit there twiddling your thumbs, waiting for a turn that never comes.
As expected, this lowered the overall value of the prize cards, and interest in Set Championships overall
For instance, Rhonas the Indomitable only costs 1 green mana with the reduction, and has fantastic stats and abilities with a negligible drawback
Heck, the Moxen are so broken in concept that versions of them that would come out years later - like Mox Diamond, Chrome Mox, Mox Opal, and Mox Amber - have all proven themselves to be pretty broken as well