LRUs often contain unrelated functions to minimize the number of LRUs and associated wiring. The VOR receiver, for example, also contains the Marker Beacon receiver, which was a separate LRU prior to Arinc 700.
ARINC 700 doesn't have a VOR Receiver. It has a VOR/ILS Receiver and it makes perfect sense to include a Marker Receiver………it’s hardly ‘unrelated’ as you claim.