A few years ago, Seth Godin wrote this book called Linchpin. Among other things, the book suggests that you hoard relationships, knowledge, and context at your job so it’s impossible for the company to replace you.
People who read books like this presumably want to continue to grow, learn, and advance in their careers. In order to do those things, you’re much better off enabling other people to do everything you do.
A programmer might refer to this as deprecating yourself. It’s a critical leadership skill that you will need to build a tech team, rise through the ranks, or otherwise level up your tech career.