In 1514, pope leo x extended the practice of indulgences across europe. what benefit would this have for the pope and the catholic church?

The benefit sought by Pope Leo X was extra funding to pay for his major project of rebuilding St. Peter's Basilica in Rome.

However, that benefit for the Pope and the Catholic Church was challenged and outweighed by the fact that the selling of indulgences provoked the Protestant Reformation.

In October, 1517, Martin Luther, a German monk/priest/professor, put forth a document that has become known as "The 95 Theses," questioning the practice of indulgences.  The official title of Luther's document, which he put forth as theses for debate, was:  Disputation on the Power and Efficacy of Indulgences.  Indulgences were papers issued by the authority of the pope that granted people removal of penance owed for their sins.  Luther objected not only to the fact that these papers were being peddled for money, but questioned many of the doctrinal foundations behind the use of indulgences.

The 95 Theses met with great resistance by the church hierarchy because Luther was attacking the money-making asset that indulgences had become for the church, and he was challenging the authority of the pope. But the common people responded with great interest and enthusiasm., and the Refomation movement was underway.

i would say that the politicial parties from state to state varies.