It makes the place pretty and hides the unsightly bits. Hard snow is also easier to climb than scree. What you don't have is solid rock. You don't have the quartzite of Federation Peak, the granite of Mt Buffalo, the basalt of Mt Barney or even the sandstone of Ayers Rock. What you do have are great heaps of rubble, mobile handholds and balancing rocks just waiting to do a number on someone.
Sensible people go peak bagging rather than rockclimbing.
Another thing missing is the bushwalkers' transport. Unlike Tasmania and New Zealand, there are no small operators driving mini buses around. Perhaps there are just too many places to cover and too many people have their own transport. The major bus companies will drop people off at points along the main roads and you can try hitching, but hitchhikers aren't so popular these days. If you want to get somewhere out of the way, you either hire a car or book one of the local taxis.