If a specific (large-scale) project has a certain hierarchy, it may be the case that those collaborators who will need to have a look at the parent item will also want to or have to look at the child items and vice versa. Instead of sharing a long list of links to all the different items and making mistakes along the way, the collaborators could just access all relevant content by clicking on the one link and seeing everything that is relevant to them immediately. They could of course still ignore the irrelevant bits, or the content manager could perhaps even decide on what should and should not be visible to all collaborators who receive the link to the parent item.