Excerpt from the link:"Under the bulk-logged recovery model, if a log backup covers any bulk operations, the log backup contains both log records and the data pages that were changed by bulk operations. This is necessary to capture the results of the bulk-logged operations. The incorporated data extents can make a log backup very large."

yes it is correct then in many artical explained in bulk-logged recovery log file not getting high size, which is true?, i checked out , in bulklog recovery log file getting high size during the operation, then what is use of bulklog recovery..