Congratulations! You have just finished implementing the last of the ShapeEditor's features, and you now have a complete working geospatial application built using GeoDjango. Using the ShapeEditor, you can import shapefiles, view their features and the feature attributes, make changes to the feature geometries, add and delete features, and then export the shapefile again.
This is certainly a useful application. Even if you don't have a full-blown GIS system installed, you can now make quick and easy changes to a shapefile's contents using the ShapeEditor. And, of course, the ShapeEditor is a great starting point for the development of your own geospatial applications.