MEL/ADL/PER-SYD-LAX is at least a reasonable progression, and more or less in the right direction, but not so BNE-SYD-LAX.
While I can't see myself ever again visiting the US anyway, in the unlikely event that I did, BNE direct to LAX on QF15 for $2354 (Feb-Mar 09) in 12 hours 50 sounds a purgatory of a lot better than BNE-SYD-LAX for $2159 in 17 hours 45 with DJ/VA.
Spend five hours to save $195, the considerable annoyance of knowing you're actually going entirely in the wrong direction ...
Just another benefit for those unfortunates who are already over-compensated for tolerating life in Sin City.