Well, basically most people including the senior managers in the organisation want to have ALL their contact details visible to most other users.
But there are also "semi" freelancers which are basicaly thightly integrated into the companies structure in a way that they work part time for and on the companies premises. But at the same time they should not be able to see ALL the contact details of the managers. For Ex. most employees are free to user to use multiple private phone numbers of their managers, while some of them should not. And since there's no way to hide certain contact fields, we have to hide the complete adresses from them
They have an adress book application which they'd like to get rid of in time, which does exactly this. You can hide single fields on a per user group basis.