The challenge dungeons are just annoying. They're not difficult, they just force you to level grind until you reach a predetermined level cap for the chapter you're playing, which forces the challenge because a lot of the enemies you encounter will always be more powerful than your party. I've been running through the challenge dungeons to get the level grinding over with and to get some decent equipment. It takes hours and your reward chest is often just a tent or a remedy. It's something I do passively while I watch TV and I end up with almost 20 hours per chapter before I get one of all the goodies.

If you're a superfan, buy it. If you're a pirate, pirate it. If you kind of liked Final Fantasy IV but only played through it once, just move on.

By TigerNightmare