I think part of it is building understanding of aspects of art/science/history/literature that you find interesting. If you have, say, a deep understanding of t

I think part of it is building understanding of aspects of art/science/history/literature that you find interesting. If you have, say, a deep understanding of the events and context of WWII (a very ambitious goal), it might not have a big outward effect on your life, but it’s very satisfying and opens the door to more fulfilling ways to engage with the subject —- in this case, say, building a collection, or going to a war museum, or meeting other people who are into this. I’m not saying that existentially it counts for anything but there are usually rewards to learning deeply about any worthwhile subject.