Googler here. I used to hate writing design docs, even though I have several published papers. But a few years back I realized the main benefits for me:
* It empties my head of the immediate parts of the idea, letting me move on to deeper parts and more productive considerations.
* It makes flaws more obvious, especially to myself.
* It makes it easier to share these thoughts, especially with people in other offices. They usually give really good feedback.
* It gives me a much better idea of how much work is involved than if I just start coding.
* It usually points out some things I need to learn before I start coding - adjacent systems, appropriate tech choices, etc.
Yes, it's also good for promo, but a successful project is better.
I often get comments on how useful my docs are, so I think I'm onto something.
* It empties my head of the immediate parts of the idea, letting me move on to deeper parts and more productive considerations.
* It makes flaws more obvious, especially to myself.
* It makes it easier to share these thoughts, especially with people in other offices. They usually give really good feedback.
* It gives me a much better idea of how much work is involved than if I just start coding.
* It usually points out some things I need to learn before I start coding - adjacent systems, appropriate tech choices, etc.
Yes, it's also good for promo, but a successful project is better.
I often get comments on how useful my docs are, so I think I'm onto something.