I have noticed a few skills that people often underestimate the importance of developing. Skills that add a significant boost to the impact of any developer. One of these is writing.
It is with a larger organisation that writing becomes important for messages to reach a wider group of people. For software engineers, writing becomes the tool to reach, converse with and influence engineers and teams outside their immediate peers. Writing becomes essential to make thoughts, tradeoffs and decisions durable. Writing things down makes these thoughts available for a wide range of people to read. Things that should be made durable can include proposals and decisions, coding guidelines, best practices, learnings, runbooks, debugging guides, postmortems. Even code reviews.
For people to read what you write, it needs to be written well. If you grab people's attention early on, they will keep reading and they will receive the message you intended to get across. More of them will respond to it and do it without few misunderstandings on what you meant. By writing well, you can scale your ability to communicate efficiently to multiple teams, to an organisation or across the company. And the ability to communicate and influence beyond your immediate team is the essential skill for engineers growing in seniority - from senior engineer to what organizations might call lead, principle, staff or distinguished engineer.