In the past it was possible to do some wild things which I think few players actually did with crafting. For example, leveling a craft to 68 or 88 for gp items, then lowering it and using them to get tier on that craft as a sub for a new craft they have leveled to max. Is there any extremely hardcore crafters out there about to get these items for their mog, delevel that craft, and take something else 60 > 100? I can't think of a good example of the top of my head but I know there are some items out there that because of the difficulty of getting tier on sub, or impossibility of it, are EXTREMELY rare.
I suppose the other good question is if its worth going this far for crafting post Abyssea and level cap raise?