Can I use Adobe's “Stage3D” to improve the performance of my 2D applications and games?

Question

I've been doing a little bit of reading about Stage3D, which will be a new API used with Flash Player 11.

Will this API improve the performance of 2D rendering (Vector) in any way, or will the library be used primarily for rendering 3D?

Any information around how Stage3D will influence 2D Vector rendering performance would be awesome.