It gives you extra land drops and rewards you for playing lands, which is exactly what this deck wants once it starts trying to chain big spells together
Being this large for this price at the time was an outstanding deal, even if nowadays it doesn't look like much, and the bonus life points were like adding insult to injury, causing players to wince looking at their hand that little bit more and do it again when you cast additional black spells
If your opponent doesn't want to take the game down to a coin flip, they can ante an additional card instead
This is especially important for Commander players, who often have larger decks
Storrev, Devkarin Lich brings a creature back if he hits our opponents in combat
You also have to mill two each time, and if the cards match all their card types, then you sacrifice this spell