DOCSP-31907 - Add paragraph from server docs (mongodb#460)

Author: jordan-smith721

source/fundamentals/crud/read-operations/change-streams.txt

@@ -142,6 +142,11 @@ Split Large Change Stream Events
 
 Starting in MongoDB 7.0, you can use the ``$changeStreamSplitLargeEvent``
 aggregation stage to split events that exceed 16 MB into smaller fragments.
+
+Use ``$changeStreamSplitLargeEvent`` only when strictly necessary. For
+example, use ``$changeStreamSplitLargeEvent`` if your application requires full
+document pre- or post-images, and generates events that exceed 16 MB.
+
 The $changeStreamSplitLargeEvent stage returns the fragments sequentially. You can
 access the fragments by using a change stream cursor. Each fragment
 includes a ``SplitEvent`` object containing the following fields: