# Superconformal description of supergravity action

I've been reading this paper http://arxiv.org/abs/hep-th/0110263. In section 4, he discusses the benefits of writing the supergravity action in a superconformal way. I have a few questions regarding this:

1. Why is (4.1) "superconformal"? I'm not sure I see how it is invariant under either conformal or SUSY transformations?

2. Why in the second line of (4.1) is he all of a sudden talking about dilatation symmetry? Is it a general feature of superconformal actions that you pick up an extra dilatation symmetry?

3. Assuming my previous point is correct and that the extra symmetry we pick up when going to a superconformal description is a dilatation symmetry, I still don't see what use this is? What do we gain by doing this? How is it helpful?

(4.1) is obviously invariant under Poincare transformations. So, Toine provides you the conformal transformations of the scalar $\phi$ and the metric $g_{\mu\nu}$ in case you want to check that the action is indeed invariant under conformal symmetry transformations.