One important aspect I learned about blogging is that a post effectively "ships" a side project, deeming it complete. A blog post allows me to move onto the next thing. It is closure of sorts (glouw.com if anyone is interested in the style).
I have a personal rule that the cost of doing a side project is I have to blog about it. No regrets on that at all, it's a small thing that can greatly increase the value you derive from the project.
I do the exact same thing! I think this pairs well with OP's point.
In the moment, writing a blog is a nice way to indicate to myself that something is done. But the process of writing the blog forces me to find some lessons and takeaways, and that makes my next project better.
