So many good thoughts and comments on this question. Since Custom Callings are not given access in LCR and tools beyond that of a regular member, that can't be the purpose of Custom Callings.
Here is what I see as the purposes of Custom Callings:
- Track who is in what calling and when they started
- Advertise to the members that they are in those callings
With the consent of our Stake Presidency and the High Council, I created custom callings for each HC showing his assignments (obviously Stake Sunday School and YM Presidents are standard callings, Audit Committee, and Building Rep are standard). So now when a member looks at the list of HC's they can see all of their assignments.
For example, the HC over YW, I added a custom calling to the Stake YW Presidency "HC: YW" and put the HC in there.
The Stake Pres can see when the assignment was added. If a member looks at the Stake YW Presidency they see the HC listed there with his custom calling.
I also did the same for our agent Bishops.
I think this is a pretty appropriate use of custom callings. In some stakes the President may choose not to do this, and that is ok, since he has the keys for that Stake.
If there is a standard calling that gives them the needed access and the needed approvals are given (Bishop, HC, Stake Pres) then that is probably ok because they have been approved by the appropriate key holders. But that brings up -- why not just use the standard calling? If there is a need to highlight a special aspect then a custom calling can be done to highlight that. If the key holders don't want that access granted then they need to instruct the clerks and secretaries to support them by sending them "appropriate" reports or partial reports.