What is the importance of studying the Prophet's characteristics for students of Sunnah, and why are the Prophet's characteristics considered part of the Sunnah?

Knowing the physical and moral characteristics of the Prophet, peace and blessings be upon him, is essential for every Muslim. The righteous predecessors took great care in transmitting them. These characteristics are among the signs of his prophethood, for there is no prophet whose life details have been transmitted as thoroughly as his. Moreover, knowing his characteristics is a sign for the People of the Book to believe in him, as Allah Almighty says: "Those to whom We gave the Scripture know him as they know their own sons," and His saying: "Those who follow the Messenger, the unlettered Prophet, whom they find written about with them in the Torah and the Gospel." Among its benefits is emulating him in his manners and outward guidance, as Allah Almighty says: "There has certainly been for you in the Messenger of Allah an excellent pattern." It also enables one to recognize him when seeing him in a dream, as the Prophet, peace and blessings be upon him, said: "Whoever sees me in a dream has indeed seen me, for Satan does not assume my form." Knowing these characteristics falls under the Sunnah (definition), because the Sunnah includes everything attributed to the Prophet, peace and blessings be upon him, whether it be a saying, action, approval, or characteristic, and following it can be obligatory, desirable, or permissible.