[away3d] Why using lines exept curves for models and other shapes

[viaria]

title pretty much tells what i wonder,
i know a story (http://goo.gl/KpyL) in 3d computer graphics people
used to use lines except curves, and a guy sad let's use curves for
this, because there was no way to make a smoth sphere.
and i can guess with flash player 10 it is cpu intensive.
My question is when we will use curves on models and other shapes? i
still see crappy models on fp 11 demos.
Thanks