DOCSP-38796 added use cases for hiding columns (#679)

Author: kyuan-mongodb

source/chart-type-reference/data-table.txt

@@ -137,8 +137,16 @@ To display your data as a hyperlink:
 
       In the :guilabel:`Other Options` section, toggle :guilabel:`Hide Column` to :guilabel:`On`.
 
-      Hiding a column preserves the encoding of a field but omits the
-      column from the results.
+      .. note::
+         
+         |charts-short| returns only encoded fields. Hiding a column
+         preserves the encoding of a field but omits the column from the
+         results. This is useful when you want to:
+      
+         - Use the field as part of the URI, but don't want the
+           field to render on the chart.
+         - Drive :ref:`conditional formatting <conditional-formatting>`
+           rules from an encoded hidden field.
 
 To remove a hyperlink from your data: