Right now, you can earn double Qantas Points on all eligible purchases with Qantas Cash® until 20 June 2014
Eligible purchases do not include money orders, traveller’s cheques, gambling chips or purchasing foreign currencies in cash. You do not earn Qantas Points when loading funds to your facility, transferring funds to another currency balance or another member’s facility or when withdrawing funds from ATMs or cashing out your facility balance. Purchases that are reversed, refunded or charged-back are also ineligible for points earn, in addition to fees incurred.
Standard points earn rate is one per $2 spent. "Double points" only brings it up to one point per $ which is the same as most decent points credit cards. Also need to watch the inactivity fees.