Final answer:
The Pope and the Church benefited from being temporal leaders by having political influence to protect Church interests, enforce discipline, and reform practices, but it also led to internal corruption and power struggles.
Step-by-step explanation:
Being a temporal, secular leader would benefit the Pope and the Church by allowing them to exert greater influence over political matters and better protect the interests of the Church. Temporal power means that the papacy holds not only religious authority but also political power, which in history, included commanding armies, forming political alliances, and sometimes even leading wars.
By controlling temporal power, the Church could protect its doctrinal purity by preventing simony and nepotism, enforce ecclesiastical discipline, and potentially lead efforts for reform when the leaders acted contrary to the scriptures.
Additionally, wielding temporal power entrenched the Pope's authority and offered a way to ensure that the Church's spiritual mandates could be supported by the force of political structures. This is encapsulated in the belief that even temporal authorities are part of the Christian body and their actions serve the spiritual estate. As such, the Church and the Pope benefited from temporal power by being able to manage its affairs independently and secure its status within society.
It must be noted, however, that the focus on temporal matters may have also led to the corruption within the Church. Popes and cardinals living like kings, engaging in simony and nepotism, resulted in less time for spiritual guidance of the faithful, and prompted the need for reform, which came about most notably with Martin Luther in the 1500s.