Holding cards for coordinated plays later, setting up powerful Songs, knowing when to sacrifice characters to banish an opponent, anticipating the play your opponent is setting up based on their deck composition
Dragon + Metalmorph Rose Spectre of Dunn = Bean Soldier + Plant S
Advertisement Lets say a player casts Bituminous Blast, targeting an opponents creature
Historical and collector value
Crow attempted to use the effect of "Raikiri" to destroy "Supreme King Dance", and Z-ARC used the effect of "Dance" to prevent it from being destroyed once per turn
The MTG commander Arcades, the Strategist (he's the classic) can turn all your Walls from meek utility creatures to undercosted beaters, allowing you to get surprisingly aggressive