Lol
Maybe in the very south they might not be needed - should be mandatory in Perth especially with most houses being double brick
Sure you want to block the western sun but eaves serve no purpose in the north or east.
The biggest energy cost is heating your home, not cooling it, thus why would you want to block the northern sun.
The northern sun, is a winter thing, not a summer thing.
I live in a wanky environmentally friendly designed home, built for a couple of million. No eaves, with a single pitch roof to let in northern light heating the polished cement slab. It never gets hot and rarely cold.