Leves can actually be a pretty inefficient path to take. I typically got more xp turning the items in to the GC. IDK how many times I got north of 500k for just one turn in of HQ product. Yes, you can only run them once per day... but you'll be hard pressed to find a more efficient turn in than something like one HQ weapon or piece of armor for north of 800k.

The point of these alternate ways to gain EXP are meant to be more supplemental methods, not the primary source. That is why they are restricted. They wanted us to be actively using the job to some capacity.