For flyers from the east coast I never quite understood the appeal of Perth as a stopover, unless you wanted to avoid transiting another country? DRW actually seems favourable to PER in terms of time/distance but the schedule is not much fun - QF1 lands at LHR around 4:30am (and Qantas no longer provides arrivals lounge or chauffeur drive).
I’d still choose SIN or DXB if I had the option. Going via PER doesn’t really save you any time… the route via SIN or even Japan is actually a shorter distance.
If youre in SYD / MEL id choose SIN everytime as least pre covid.
I guess for QF though, PER allows for significantly more 1 stop connections than SIN and in some ways trying to compete with SQ and the like with the hub model.