Bicephale gives Seaside the capability to deal with simple static pages which have "REST" urls, integrating that with Seaside's sophisticated call/answer mechanism. This means that you can now use Seaside to easily build a website which has simple "normal" s urls for the viewing parts, and sophisticated seaside sessions for the "editing" part. And as a developper, you never need to get out of Seaside's model to build it.