For example, if we were using the name of a topic in a sentence, we might not want it to say exactly what the name of the topic is.
It's basically rewording the topic name, but linking to the topic at the same time. So we need to be able to edit the text in the link, just like in any other HTML link - where we choose what the text is, then link to any topic we want to.
Thanks for the feedback. The ability to rename content links in Guides has now been developed and will be out in our next release.