Yeah, but he also brought Treebeard to Isengard, leading the ents to overthrow Saruman. Did that not make the list?

He did plenty. In the movie he lit the beacon to call Rohan. Fought in the battle for Minas Tirith, where he saved Gandalf's life. Saved Faramir's life. Saved Merry's life.

Sauron himself questioned Pippin and came away with the conclusion that he should apply his army and attention toward Minas Tirith and Gondor rather than continuing to look for the real ring-bearer right under his nose. Essentially made the entire gambit with Frodo possible.

This has been a pro-Pippin PSA