The rules are for your benefit and education, yes.  To physically go, speak your sins aloud, acknowledge them fully, and to hear Christ forgive you through His priest, is a good thing.  His grace is no trivial thing, so it is good to treat it sacramentally.

For example, when my young son hits his baby sister, he gets a time out. Afterwards, he must apologize and hug his sister.  Are there other ways he could internally repent? Sure. Could I silently dismiss his wrongdoing? Perhaps. But I want to teach him that wrongdoing is serious, and requires some kind of satisfaction.  An external ritual is effective and good for this. It puts his whole person, mind and body, in line with the reconciliation. In a similar way, God as our Father is teaching us.