How to understand the purpose of the Purge script and Purge-em script in EngageOne

Product Feature: Utilities
The purge script is designed to deal with all documents in EngageOne regardless of whether it's OnDemand or Interactive. 
The purge-em script is for purging the Event Monitor DB. 
The WF_Task, WF_transaction tables are related to WorkFlow and should be addressed by the purge script. These tables are referenced by WorkItems and should be purged in unison with the WorkItems. 
UPDATED:  November 6, 2017