You can have two or more views of a document open at the same time, and work in either or both. The radical zoom capacity of this program actually offers useful new ways in which one might work on document. InDesign has document wide layers that work much like PhotoShop layers. Speaking of PhotoShop you can drag and drop Native PhotoShop and Illustrator files with all layers intact and fully functional to InDesign. Illustrator files remain fully editable inside InDesign.
Every vector component stays discrete.
And when you are ready to go to press you can crop the images on each layer to their frame, thus saving on final file size. You can also place pages from PDF files as linked graphics. InDesign is essentially a PDF distiller, since files can be saved directly to PDF format, and includes a variety of save options, including a choice of compression levels, font embedding, password, and color conversion. Adobe, like Apple with OS X, is using the PDF format in the low-level functions of their programs. The message I got from the seminar is that PDF will eventually displace EPS as the standard everywhere.