Memorial to Folly

The trade here is patience for inevitability. A black source that comes in tapped already costs you a turn of tempo, and the recursion mode taxes you again: three mana and the land itself, all to buy back a single creature. That is a steep tab to settle for one card. The compensation is that the cost is paid out of your land slot rather than your spell slot, so the regrowth effect rides along inside a card you were going to play anyway for its mana. Think of it as a utility land that spends ten quiet turns making black, then, once your hand runs dry and the board has ground to a halt, returns a creature you already lost to your hand. The ability carries no timing restriction, so the sacrifice can fire during an opponent's turn or mid-combat to bank a threat before you untap into a fresh play; the three-mana-plus-land price, though, means you rarely get to be reactive with it. The tempo hit usually forces the buyback into a stalled main phase where card advantage, not surprise, is deciding things. It is a slow card built for slow games, and the entering-tapped clause is the honest admission that a land doing two jobs should not also be doing them on curve.