This probably seems pretty obvious but there was no way until the June CTP build to fill a ListObject with data and then disconnect it from the underlying data source---effectively doing a read only databinding to ListObject.  There is now a Disconnect method on ListObject that can be called after you have filled a ListObject with data to leave the data in the Excel list but disconnect from the underlying data source.

This feature is useful when you just want to get a bunch of data into a ListObject and you don't want edits in the workbook to affect the underlying data source.  Also, when ListObject is bound to live data, it won't allow you to add new columns at runtime and places other restrictions on the edits you can do.