What is the function of the Contact Type field on the User Profiles screen?

What is the function of the Contact Type field on the User Profiles screen?

The "Contact type"  field is a new field used to advise which users within the company should receive specific communication from PaySpace.

The contact type option 'Payroll Contact'" contact type will receive newsletters.

Users can be attached to one of the following "Contact Type" options:
  1. Contract/MSA Contact
  2. HR Contact
  3. Invoice/Billing Contact
  4. Primary Contact
  5. Payroll Contact
  6. Technical Contact