There are certain dungeons that aren't tied to the msq, but these are because they have literally nothing to do with the msq. The ones that are tied to the msq are there because they literally develop the story. Looking at how they design content, they don't have anything that's, 'Here, just spam this for exp, later'. There aren't any pointless instances in game, all of them have a purpose. Not up to stone Vigil? Yeah, the adventurer isn't gonna risk his neck diving into a dragon's nest on a childish whim. Having a reason for the madness is part of why this game is so great. Everything has a purpose, everything has a reason.
