I think they just left it alone since you could gather a ton of antumbral rock easily if the turn in was any good. The turn in for crafters is really just to get the new/ rare items back when you fail to HQ a synth, probably to put less emphasis on the use of reclaim (though a NQ synth still loses you a modest amount of gil from other materials). There is a turn in for magicked oilcloth/ bamboo paper to get some gathering food. I forget what it is, but of course you can get the cloth/ paper from leves, allied seals, or grand company seals.