If I'm not mistaken even after you get the new card, you'll still need to reactivate with the new Qantas cash card to transfer it across. I assumed until this is done, the old card keeps working (the Qantas Cash part have a longer e.g. 1-2 months expiry compared to the QFF part).
Yes, that's what I had assumed but the woman at QF call centre was quite certain that what I outlined above was the case. It does seem extremely strange to me.