The best example is a user who is not always active on their PC, but is within earshot to answer calls, or the user only has a desk phone with no presence. This makes a lot of sense for a lot of use cases, however close every deployment I have been involved with has a use case to deliver calls regardless of the users presence.
When using the Skype for Business or Lync Response Group service (RGS), agents need to have a status of available or inactive to be delivered calls.
