Tifa Lockhart enables a potential turn 3 kill in Standard
This is important, as whenever Nethroi mutates, its controller can return any number of creature cards with total power 10 or less from their graveyard directly to the battlefield.This can bring back a massive board state from the graveyard with the effect of a single card, potentially swinging the game in its controller's favor
It can deal four damage anywhere or make itself indestructible with lifelink, both great effects with different usages depending on the game state
Cards like scheming symmetry, brainstorm, crystal ball, and a number of scry cards can put your 6-9 mana spells on top of the library, so that Yuriko will bleed your opponents for massive amounts of damage each turn
Hilariously, it's also implied by the Invasion of Segovia card that said single soldier still ended up losing
That was fine and good, but like all things including the use of mass removal, things change with time to adapt to the circumstances