Some combat spells are never used?

[llamabeast]

This is largely true, but occasionally the close combat ones are invaluable. e.g. the puny touch ones may sometimes enable a mage to kill an assassin. The larger AOE ones can come into play if enemy troops manage to sneak round your front line to attack your mages - sometimes one of your mages may take the initiative and fry the lot of them.

They are hard to script though - it's very rare to successfully use them deliberately. I suppose you could have an SC who's got high fire or air magic or something, and script him to attack/attack/Flame Eruption/Flame Eruption/Flame Eruption. Could be quite effective.