It would be great if a selected point in Graph Builder could be labelled with new information right there.
So basically, it's a mixture of Row Label and Annotate - new text that is connected to a data point.
Maybe one could select a point, right-click -> Rows -> Row Label with New Information, a small window would open up with a field for new text, and when clicking OK a new column would be created (in the background) and labelled, and the new text would be written into the selected row for that column and the row also labelled.
Maybe there could be further options to select an already existing column as target for the new text info or sth like that. This would help if one wanted to do this with a number of points and not create a new label column for each point.