The most important thing about PowerPivot is the ability to share users analysis into SharePoint so that these other users can slice and data form within a browser. As I’ve said before this uses SQL Server analysis services behind the scenes, albeit as part of a special install option. I’ve also said that PowerPivots on SharePoint are not anywhere near as scalable as conventional analysis services, and so the usage has to be carefully monitored to make best use of the facility. This monitoring is built into the PowerPivot functionality in SharePoint 2010 via a dedicated dashboard.
The other clever thing about this installation is the ability to schedule refreshes of the PowerPivots from their source data thus keeping them up to date without any intervention.
I have another screen cast of it on TechNet Edge here.