Besides assisting in easy clean up, parchment paper provides more even cooking and baking and a neater way to make straight cuts in baked goods. For more details, see: https://www.thepioneerwoman.com/food-cooking/cooking-tips-tutorials/a93622/7-reasons-to-use-parchment-paper/
I resisted using parchment for a long time to wanting to start with a single use item. Then, on America’s Test Kitchen (or one of its other franchises), they said they use it until it falls apart. Now, I almost always use it so I don’t have to scrub the cooked grease/oil off my pans.