Haha, it's an element of endgame, of course it's complicated! Until you hit level 50 though, you can amuse yourself with the lower level leves for bonus gil and items. I forgot to mention, the lower level ones are the only way to get parts of the Onion set. They also drop "tarnished" items, which can be synthed into higher level vintage items. Also, faction leves are deemed quite significant in the Lodestone history: Every time you finish one for the first time, you get a notification there.

Speaking of which, something amusing about leves in general: The game keeps track of every leve you've done at least once. When you've done a leve before, it'll have a red stamp on when you're looking over its information. Also, on a related note, for the faction leves that drop the rune stones? You only have to go up the chain once. Once you unlock the highest tier, you can do it over and over again, so long as you have points.