What is the point of Regions/Sites?

What is the point of defining Regions and/or Sites if you cannot associate Requesters with those? The only thing I see when I edit a Requester is Department Name, and the ability to allow/disallow "Allow to see all requests for the department".

Unless I'm misunderstanding how Regions/Sites pertain to other companies, I invision having each user associated with a site, with Regional Managers (other users) associated to regions, and granting the ability for Region Managers to see all frequests for their sites/regions. I could grant individual users the ability to see tickets from their entire site, but it appears this is a department-level item.

Can someone explain how regions/sites is supposed to fit into this access logic?