[Deadnature]

I've noticed that my Abysia PD fire-mages will cast flame eruption if the situation calls for it, IE: multiple enemies are within range and said mage has enough fatigue/skill. I would imagine this spell would be quite nasty against a none-fire-immune army.

So the caster WILL use it in the right circumstance, but you need to keep him alive long enough of course.

Check out the thread on using Pangaea's Dryad songs, a similar strategy would probably be necessary if you want to use such fire-spells offensively.