While trying to make an argument map, I have felt that this feature would be priceless. Some things can be done in Excel, and then the visual format of the argument map helps in expanding this graph rapidly. But after that, yEd cannot work on the content on the nodes. Therefore we have to export the content once again to Excel and process it outside yEd, and then re-import the graph once again inside yEd.
That's how it is important to expert the data to CSV or Excel file.