Hilton deposits very very few Hilton Hawaiian Village deposits into RCI. Owners also have NO control over which resorts do get deposited into RCI. So you can't count on an owner depositing, you must count on Hilton depositing, and they do not deposit very often.
Since Hilton GVC also has other options for your points (other partner programs and Honors points conversions), if you use those options, HGVC needs to raise funds to off set the cost of that point usage outside of the HGVC system. So HGVC rents units out to the public. Why rent Vegas or Orlando units when Hawaii units, especially HHV units, rent at a premium.
You can rent HHV TS units from hilton directly, but I wouldn't count on a trade there. You might get lucky, so never say never, but the odds are against you. Now if you really want to go there you would have a better change renting from an HGVC owner directly.