Why does the content of the A and R lines have to link back to T line?

In some very helpful feedback for a recent question I asked, it was suggested that the actions and the result link back to the T-line. I can see how this is cleaner but I am just curious about the utility of this when doing future models. Other than seeing that I am setting up a self-fulfilling prophecy, why is important that the R link back exactly to the T? Thanks!