According to this and other references Pig is better than Hive to process unstructured data. So, the data first cleansed with Pig and then processed with Hive.
But, in the data factory, data may not be in a nice, standardized state yet. This makes Pig a good fit for this use case as well, since it supports data with partial or unknown schemas, and semi-structured or unstructured data.
Would like to know more how Pig can handle unstructured data while Hive can't.