People who confess frequently often stop committing mortal sins. Sometimes they just list a whole lot of venial sins without much thought. I think the OP is talking about confessing fewer venial sins, but going more deeply into the causes so they can be rooted out.
It’s an orderly way of advancing in virtue. Rather than confess every tiny transgression you can think of from the last two weeks (or whatever time period), you can choose to concentrate on getting rid of one or two of the recurring sins at a time. This is called the particular examination of conscience. With the advice of your confessor, you choose your area of concentration. Every day you check on yourself to see how you’re doing. At your next confession, you confess your failures in this area (along with any mortal sins or venial sins that took you by surprise and horrified you). Your can discuss why and how you succeeded and why and how you failed and get good advice from the priest. When you have made substantial progress, or even conquered this sin, you move to the next one. Eventually, you work on the acquisition of virtues in your particular examination.
For example, if I regularly snap at or interrupt my spouse, I might choose to work on this as my particular examination of conscience. I will pray about why I snap at him and may discover impatience rooted in pride. I will make a resolution to give due consideration to his ideas, letting him finish speaking before I cut him off. Some days I will succeed, and some days I will fail. I will bring it to confession and discuss it with the priest. I may discover that my husband is right about certain things because I’ve given him a chance to express himself. I will grow in humility. When I no longer interrupt him regularly, I will choose another thing for my particular examination and start the process over again.
I believe it was St. Josemaria Escriva who said that the general examination of conscience (looking for all your sins) was a defensive weapon (your shield) and the particular was an offensive weapon (your sword) in the war against evil.
Betsy