Sorry do not agree.
No passenger is going to stay in one place or "keep within their same seating area" on international long haul flights from/to AUS. QF1/2 are full for the next several weeks so that is a lot of PAX flying 17hrs+ each way, all walking around stretching their legs, all queuing for a toilet, etc
I am not a covid expert and I assume neither are you so comments like "a covid-positive person only spreads it to people near them" is hilarious - absolutely no fact whatsoever backing that up. Multiple cases have resulted from people getting infected from merely being at the opposite end of a large room with no contact with an infected person, or eating in a large restaurant in seperate dining rooms and getting infected.
By all means take as many sensible precautions as possible but when you fill every seat in economy along with people removing their masks multiple times throughout a flight to eat, drink, breathe, etc QF cutting snack bars 'as a safety measure' doesn't make any sense except saving cents.