The Cabin Crew situation is quite different. Many of the pax flying between Oz and Asian destinations do not speak English. They feel more comfortable if there are CC who can speak their language and look familiar. That is simply a comfort and commercial consideration. It can also be argued on grounds of flight safety, when emergency instructions in the appropriate language can be delivered by native speakers.
Most pax never see the Tech Crew, so their ethnic origins do not matter, just their professional abilities.