They are a means to an end. If you have level 90 or above gear, they are useless. OK, 20 of them resets your Chocobo points, etc. But so do 48,000 seals, and you probably already have that from doing other crap and having nothing else to do with seals. 20, 30, and 40 seals = level 90 gear. At 6 to 8 seals a day, you get them prettying quickly. You can also use them to buy ventures... Oh wait, so they're not completely useless.

I do them, but I won't spend more than an hour. I'm fate farming for atma right now (Thyrus), so I don't mind farming in that area, unless I have the atma. I've actually used it to level up other classes. I hunt with my WAR or GLA when I can. I don't know if I'm just lucky, but I've run across a couple of the monsters as well just doing the hunts. Then I get tomes, Allied Seals, and gil. Been pretty good so far.