Actually confession is a tool that the Priests use to keep informed of what their subjects are doing.
It's a great way to control people, get sexual favors and material things like money.
Say Father O'Leary has the hots for Mary and would love to get in the sack with Mary. When Mary confesses her extra material affairs to Father O'Leary, it gives Father O'Leary some inside information he can use to try and get in bed with Mary.
Say Father Smith has is gay and the hots for Jim. When Jim confesses his sin of having gay sex with Bob that gives Father Smith some inside information he can use to have sex with Jim.
Say Father Johnson is a p*d*file and loves little Jimmy in a biblical sense.
When little Jimmy confesses about problems in his family life it gives Father Johnson some inside information that he can use to get a some biblical love from little Jimmy.
Say Father Carter gets caught stealing money from the Sunday collection by Susie. Well Susie has been to confession a number of times with Father Carter, which gives Father Carter some inside information he can use to blackmail Susie from snitching on him. And if Susie snitches on Father Carter, Father Carter has so good inside information he can use to discredit Susie.
That's what confessions is all about power and control.
Confession is used by the Priests as a fantastic tool to control their flock.