Which of course brings us back to what are essences and so, what's up with Moggle? Which beings us back to strawman theories, which brings us back to in-game evidence, lol. If the Ascians were able to teach the same method used to summon primals to moogles so that they'd summon a bedtime story, either there's more to summoning than Minfilia thinks or there's more to Moggle than she gives them credit for. The main reason my theory stuck with the former is because it better explains Louisoix, fits in with an obscure clue Fernehalwes gave once upon a time, and makes me think harder.

It could very well be as simple as Minfilia says, though. We'd do well to not forget that.