After the confusion related to the act of zealotry of Pinchas was settled, his role was clarified. Pinchas was given the promise of eternal priesthood. He was told that his descendants would survive forever and fulfill their eternal role. They were to bring atonement to the Jewish people. This atonement was achieved in the Beit Hamikdash and continues to be the role of the Kohein to this very day.
In the Temple, they offered the sin offering to bring atonement to the one offering it. Not only was there a specific Kohein that cared for that individual, but the atonement was not complete until that Kohein finished eating his portion of that sacrifice. The one offering could feel satisfied that he had achieved full atonement, when his Kohein finished eating his Korban.
Today in Israel, the Kohein blesses the nation 450 times a year. Each time he blesses, the Shechina, Divine Presence, magically passes through his fingers. The role of the Kohein is to bless, and these blessings have power.
This blessing is also capable of helping to bring atonement and all kinds of good things to the recipient. Pinchas began this process of atonement, that continues until today.