Say for example you do a Where Used on a page. In the Uses tab, you'll see the Component templates, but not the building blocks used to implement them. (If the page template is inherited, you won't see that either, but for now let's keep that out of scope.)
My suggestion is that the template building blocks should also be shown. I understand that perhaps this is more interesting to developers than to others, so perhaps this could be governed by a user preference.