Part of the problem here appears to be that there is a variation between vouchers. As Ozstamps knows (please don't ask) I have a variety/mix of vouchers. Some are exactly as per the post from "serfty" and some are slightly different and state

Standard Terms & Conditions:

* Valid at Hilton Hotels in Australia & New Zealand.
* Certificate is fully transferable
* Voucher is valid for one nights accomodation in a Hilton Guest Room
* Subject to availability
* No further discounts apply
* Certificate is not replaceable if lost or stolen
* Certificate must be presented to redeem benefits
* Certificate can be used in conjunction with other certificates
* Valid for 12 months from issue of membership
* This rate is not eligible for Hilton HHonours points or airline miles

There are some other variations also. Sorry NM you are wrong on this occasion. Most unusual!

It was a $120 voucher with these terms and conditions that I used at Melbourne Airport Hilton and as I stated "was upgraded to a mini suite, got HH points, a stay credit and QF points. Great, yet way beyond my expectations or entitlement.

Don't know if it's the HH Gold status as theorised by QF WP or random luck but I'm happy to accept the bonus.