Can you spot the strange thing in the following JSF page?
It looks like any other web page created with JSF, but the "strange thing" here is that three of the sections on this JSF page are actually Portlets.
This is probably the thing that is most important for JSF developers in the new WebCenter product. It allows you to embed a Portlet into your JSF page. So in a sense the JSF page replaces the need for a portal page.
Since you can also now take JSF pages and create Portlets out of them, you end up with a very reusable architecture for creating areas on your JSF page.
The new WebCenter tutorial can walk you through the steps of creating this.