It's like the original Final Fantasy series. The designers have thought of many ways of defeating the monsters. A classic example is the undead dragon on FFX which dies on a single hit if you toss it a phoenix down. The game even goes out of it's way to hint you about the monster's weakness.
Final Fantasy series always been about the choice of either resort to strategy to beat hard enemies early or grind up until you're strong as a "god" and bulldoze your way through the rest of the game.