When you connect to some backend via the Flash Builder "service inspector", it autogenerates alot of code, which seems to be giving you some additionel intellisense. I'm very interested in some documents that describe whats actually being autogenerated and for what reasons. Because when you don't use the service helper, you can connect to a backend in like 2-3 lines of code.
Generally, the more specific you can be in programming the more efficient and less error prone the code is. The downside is that explicit declarations require much more typing.
The auto generator attempts to generate code that is as specific as possible, and provides you some strongly typed methods to wrap the calls in. The VO objects probably look the most strange, but I think a lot of that is just explicit binding declarations. There is also some functionality added for advanced server setups (like lazy loading and such).
But you don't know any docs that explains this further?