I'm not attempting to sound like anything. You simply chose to dispute my original claim that Reuse would only serve to devalue crafting materials and crafted goods, even as you parroted the basic facts of macroeconomics that should lead you to quickly conclude otherwise. In such situations it's best to make you walk through it step by step so you can arrive at the correct conclusion through your own reasoning. You sure do seem intent on making this personal though.
As for why Reuse and not maps are the problem, the answer is simple: Reuse is entirely superfluous. SE has fairly direct control over the availability of pretty much everything in the game, barring some influence stemming from player behavior, so if they want more materials in the game, they can simply increase the drop rate for those materials. It's not that there's something intrinsically worse about an indigo cloth that exists because of Reuse–any particular type of material is entirely fungible–but that it has no real reason to exist and doesn't actually help anyone worth worrying about. Since we've now established that Reuse will in fact just hasten the decrease in the equilibrium price, you may save money on materials at the start, but the consequence is that the price you can sell your stuff for drops more rapidly. As the sale price drops, so too do the raw profits generally drop, and you end up making less money per craft. However, you can't actually make crafting more efficient until several months from now when new gear comes out and makes current crafts easier, so that also means you make less gil per time spent. The money you saved on materials is extracted from you in the end by making the crafts more inefficient. With greater and cheaper material supplies, you'll generally also face more competition than normal, further depressing the price beyond what it would otherwise be at.
Since it's trivial to include Reuse in both specialist and non-specialist 2 star crafts, the effects on the economy will be widespread. The only people who will benefit from this are players whose income is largely independent of the player economy, which is to say players who only interact with it to buy and who will benefit from lower prices because it increases the purchasing power of their largely static income. Such players aren't worth considering though, because they've freely chosen to be poor, since they don't even bother to use their free retainers to sell the garbage they pick up off the ground for more than the vendor will give them.