For me at least, writing is one of the best ways to synthesize and hone your knowledge.
It forces you to reflect on what you have learned, distill it into a group of succinct learnings, and then reflect on how best to share them.
IMHO & experiences, honing your learnings and thought processes are one of the best ways to push yourself to be a better mentor, leader, investor, etc.
Vs. just shooting from the hip.