Glad you liked them
I was actually thinking about them on one of my flights - wondering why I didn't like them... and it comes to the design.
Every other airline has slippers with a firm 'bridge' meaning you can wake up and slide your feet right in and go to the WC. The QF ones you can't do that - you actually have to bend down and lift the roof of the slipper up so you can slide your feet in. Fiddly. More so when travelling with an OAP.
The only thing i could work out was it was design vs practicality.
Clearly i have too much time to think about petty things :shock:
(and yes, i take my own slippers on QF flights... )