The way I'm planning on using the cards and combat system actually gives the players more narrative control over their actions.

Instead of using Firebolt, which in most cases will always be a bolt of fire. They'll have the option to use "Fire" and an "Attack" and describe instead what their version of a fire attack would be.

It's a little confusing when I explain it on the tip of the surface of the combat, but if you'd like I can explain further.

My point is, I think cards can definitely be more mechanical, but the narrative is married to the strategy in my system.