Can you provide specific use cases? For example, what would you do differently if such distinctions are available visually?
Composition and parent-child references primarily affect what happens when objects are deleted. It really doesn't affect visualization.
Any details you can provide would be helpful.
As Kenneth has said, essentially the problem is that there is no easy way to determine where different reference types have been used unless you interrogate the element in very specific ways, which makes it difficult to use this feature effectively at scale. Suggestions that wouldn't make the UI cumbersome:
1) It could be a hidden Status Bar option alongside 'Show Unique ID' that could be manually enabled by users.
2) It could be included as an option in the Element Search dialog, allowing you to find instances of a particular reference type being used