Grove of the Burnwillows

The asymmetry is the bargain: the painlands that came before charged their own controller for color, while this one charges the opponent instead. Karplusan Forest, Brushland, and the rest of that early cycle take a life from you to filter into two colors; here the colored mana is free to the controller and the opponent receives the trickle. That reversal sounds like a clean win until you ask which decks actually want it, and the answer is counterintuitive. A deck racing the opponent's life total to zero cannot afford to hand back points, because every life it donates is a life its clock has to chew through again. The decks that genuinely don't care are the slow ones: grinding shells that win through inevitability, recursive damage engines, big-mana ramp, anything whose plan ignores the opponent's life total entirely. To those decks an untapped, never-self-damaging source of red and green is close to free, and the gifted life rarely changes the outcome of a game already decided by attrition or a lock. The wrinkle is the matchup that becomes a long damage race or a mirror grind, where the donated life compounds back against you, and the rare card that punishes opponent lifegain can flip the upside outright. But the design holds because it loads its cost onto exactly the games the typical pilot was never going to lose to a single point, and waives it where one life never mattered.