The only reason I'm against this is because gil is not a necessity, especially if you don't craft or gather. The average Joe player does not really need bags of gold to sustain themselves. The vast majority of battle content means you aren't using gil for anything but teleporting and repairing. Hell, the game even offers you materia on a plate.

It's a good idea to combat botting and unsanctioned RMT, but the sort of people who would benefit from this... don't really seem to need it in the first place.