Why do RC.0 project declare components twice in app.module.ts?

MyApp and other page components in @NgModule declare both in declarations and entryComponents, I think it is unreasonable and should be simplified like the ionic 2.0-beta11 way…

In ionic2.0-beta11 project, one app.ts can start the app, and no need to add all the page…

is this change due to the ng2 structure? any method to optimize?