Oracle Customer Data Hub (CDH) is not a mandate for EBS users. However, it solely depends on the Organizational needs. If an Organization decides to have SSOT (Single Source Of Truth) for it's customer data they can go with CDH solution.
CDH is a complete packaged solution that allows companies to create a single, enterprise view of their customer base, by consolidating/synchronizing customer data from heterogeneous systems into a central, operational, data store. CDH alone will not suffice the requirement. CDH ties with Oracle Customers Online (OCO), Customer Data Librarian (CDL), and the Oracle Trading Community Architecture (TCA) to create a robust, scalable, central repository of duplicate-free, enriched data across a heterogeneous landscape.