Intelligent and effective addition to SharePoint 2010
JEFS is one of the SharePoint-related hidden marvels of CodePlex. It is a tool that can potentially make life easier for both developers and IT professionals alike. When taking into account the different areas of SharePoint that JEFS can be invoked from, it feels like a natural extension to the SharePoint platform.
2 - Allows better and clearer code management on the client
3 - No longer needing to manage code in SPD / CEWP