Divinity: Original Sin series has magic that can be impacted by combo effects. Poison + Fire produces an explosion. Air + Water makes electrified ground. Fire + Water produces steam clouds. There are many interactions like this based on elements and they can be applied by mundane means through enchanted arrows and grenades.

Dragon Age likewise had spell combo effects such as Crushing Prison + Forcefield which mimics the answer to what is better, an unstoppable force or an immovable object. The result being a colossal explosion that affects everyone in area around the target except for the target.

Basically, spell combos encourage diversity, even in MtG.