For sermons, the label tells us the primary passage being preached upon which allow us to identify relevant sermons without working through a list of all references to a given passage. Monographs which in the Guides are handled in the Collections section only give us a list of all references. It would be a major advance in Logos to be able to see only those that are actually studies of the passage. How big of an advantage? See Index of Bible Studies to see the dedication of users to this function.
As it is a case where it might be cost-prohibitive for Logos to go back through all their resources, I would suggest that one rely on crowd sourcing to get the data - something along the lines of the Sermon label or the Community tag.