User blog comment:JohnnyN64/Mysteries of Fairy Tail/@comment-6152051-20140611062120/@comment-7418318-20140612085449

Do you mean only the Zodiacs or all Celestial Spirits? Because I have trouble thinking of Pyxis, Caelum or the Horde of Canis Minor as former Humans.

@Jonny: I agree that Deliora was not petty, but neither was it enough of a threat to justify Etherion. Etherion is a country buster after all.

With Deliora there were survivors in the destroyed city. We saw dozens of them on Galuna. But where Etherion hits, nothing remains. It's the magical equivalent of a nuclear strike and a very big one at that. Such a weapon of mass destruction isn't used against a single opponent unless you have exhausted all other viable options... or are manipulated into it by two clever infiltrators in the Council.

If they had fired Etherion, they would have done more damage than Deliora, unless the Demon happened to pass through a very large uninhabited or sparsely populated area.