You're totally right. I wouldn't. I probably wouldn't even make a game accompanying it, because I don't really like pulling things out of nothing but air, without anything to relate to. I'm not that creative. But I love to read, listen to or play marvelous stories and adventures. That's something I really do like and like to talk or write about. Sometimes. That also applies to the opposite of it but to a much lesser degree. But back to the topic.
To be frank, I really can't imagine atm about what game or even world you're talking. From my perspective all there is atm is a quite good looking barebone-sandbox with some bits and pieces of story attached to it. A bit more in front than in the aft. A world...well, there is none so far. Unless you call a 2D-map, a home with a handfull of render, a two-render bar, a one-render café and a spa with some render a world. Limited to graphics of course. Not written word, because there is just none or not much related to world-building atm. That's not to say that there won't be in the future. Hence the preliminary "review".
So to conclude, I can't imagine what you're writing in your book. About the game? Nope. About the story? Nope. About the world? Nope. About the graphics and how you are doing them? Well, yeah sure. That could be quite interesting I guess. But for me that would be a book about graphic- and art-design, not necessarily a (or the) game. Because there is just nothing to write about, yet.