Yes. In addition to this, even if a thing is really obvious to many or most people it still might not be common knowledge, and it’s good to write a post that can become a standard reference that most people believe most people have seen, that people can link to, etc.
What is your relationship to your username?
Agreed. I would also love an easy way to ask or answer “Huh, I’m having a hard time understanding this. Do you know of any explanations in X format?” The worst case when writing something that’s already written (assuming you do it well) is that you waste a bit of time, but you can probably expect that your configuration of words will happen to be a better explanation for at least one person than what exists.
As for the username, I played the devil’s advocate one too many times and someone used it as a nickname for me. I was already a fan of “Screwtape Proposes A Toast” by C.S. Lewis and it fit the pattern for names I respond to easily, so when I made an account on Less Wrong I picked that.