We can link assets in between using the asset link field. When doing this and having 300 devices under a license or under a switch/firewall/etc the related items area becomes a disaster.
Also the double link logic is not applied if we have matched fields in between two diff assets (e.g. when using a device asset with a field link to licenses and have under the licenses asset a devices field link does not show the linked device under the license asset devices link field). Instead related items is used.
Related items can remain for KBs for example.
There might have been a few features requests related to this in a way or another.