Some examples of meaningless spell casts displays:
When resurrection is cast on a creature that’s already alive.
When major healing is cast on a creature that’s at full life or already dead.
When a damage spell is cast on a single enemy that is already dead or a hit-all damage spell is cast and there are no living enemies.
All of these still cause the graphics delay of the spell being cast.
Since casting the spell effect still might trigger other effects (e.g. Spectrum of Eternity), the text is still useful, but the graphics display just delays the battle. So, an option under “gameplay” which causes just the graphics display to not occur and the spell casting text to change to add a bit, e.g. “Doom Devil casts Major Healing, but the spell itself had no effect” would be great - it would probably reduce my battle time by 10% or more.