If you check delete table table before loading, your table will be truncated before the data flow starts. A SQL truncate cannot be rolled back. If your job fails, you cannot recover your original data.
As a workaround, include a script to saveguard your table before starting the dataflow. Use a try-catch structure to intercept any errors. If your data flow runs successfully, drop the copy of the table; if it runs into an error, put the original contents back.