While Pega on-prem installation always comes with 3 differents schemas of Pega DB - PegaRules, PegaData and CustomerData, but both PegaData and CustomerData Data-Admin-DB-Name points to same default schema - i.e., PegaData.

This leads to a confusion when creating a custom/Non-OOTB data type. The physical table actually gets created in PegaData schema. But, Modify Schema landing page on Pega Dev studio incorrectly shows the new table under CustomerData schema (it shows OOTB customer data tables like p_contact that are really in CustomerData Schema + custom/new table that are actually in PegaData schema). 

While I understand that CustomerData Data-Admin-DB-Name can be easily pointed to CustomerData schema of Pega DB (or even an external DB), but my question is -

Why the default Pega configuration of CustomerData Data-Admin-DB-Name reuses PegaData connection (default schema PegaData), and NOT by default points to CustomerData schema?

Thanks