What functionality is missing? What is unsatisfying with the current situation?

As a Campaign Runner you can't make Player Character's public that the Campaign Runner created with NPC's as hidden. And those Player Character's can't become public if they have no Guild Membership.  

How does this feature request address the current situation?

Currently if you assign an NPC to a player that is hidden, and they don't have a subscription they cannot make it visible. With this feature this will be fixed, another solution would be to automatically make the PC's public.  

What are other uses for this feature request?

There are no other uses, but this will fix the workaround of transferring the character and making it visible.