The answer to your question may not be what you are expecting, it is actually technical limitation which is causing the Gree currency to be character bound. Within our current system we had a few options:
Those were our options from a tech standpoint and our justification for the decision we made. Hope that makes sense!
- The items are character bound and stackable (the way it works currently)
- The items are non-stackable and bound to Legacy. (we did not choose this option to avoid a cargo bay somewhere full of currency)
- The items are fully tradeable (these are meant to be earned, at least for now)
So how come you have a technical limitation with the Gree currency but not the bounty contract currency? What is the technical limitation, if you know?