Ok, so there you are playing with RNGesus, and after a while you start building up stacks of weird stuff, all of which becomes totally useless, untradable, unsellable, basically worthless. In some cases, like with Camel hair or urushi, you have to do a lot of quests, or spend company points to buy them. The only difference between these mats and something like Coke or Peacock ore, is those items can be traded, sold, and the primary recipes they get used for have later recipes for things like armor and furniture.