Technical container for contacts

In the hybris Marketing 1511 sharing of facets (e-mails, phone numbers, etc) are not allowed. Shared facet (e-mail address) is removed from the contact and put to a technical (container) object in the root table.

There are no references for a contact to container whatsoever. Data is basically lost, if contact with a same facet data is imported in the system.

What is a purpose of removing shared facets from contact data and creating a technical (container) contact?

Regards,

Maris