Jaba, Le Dugong uses (early days) around-about 80kg/Pax less fuel LAX-MEL compared to 744ER. = Huge efficiency gains.
AND carries a whole lot more pax.
If you need to move a lot of people a long way - A380
If you need to move 2/3'rds as many a long way - 744
If you need to move 1/2 as many a long way - 777
(If you need to move an A380 load in 2 steps = 743)
QF have been doing it better than most for a long long time now. I reckon they know what they're doing.