Here are just a couple off the top of my head (doesn't pertain to my usage) set of use cases.Use Case 1:Because people in support (department) may need to open tickets for the billing (department).Especially if your billing department only works mon-fri, but your support department is open 24x7.Use Case 2:Tiered escalation. People in your support (department) may diagnose a problem/bug and open a ticket for the development (department) so that it can be addressed in a patch. One may not wish to grant direct access to their devs.Use Case 3: Billing (department) may need to open a ticket for the support (department) because a user may be having a technical issue connection which they thought was billing and is not. Especially true if you the person calling gets disconnected, or if you have a live person monitoring a support email address and opening tickets manually.And those are just the first three off the top of my head.