Hmmm I dont agree with that. Essentially this is a book with pictures, those usually dont cost all that much, according to a quick search its from $13.95 to $17.95 although I'm not sure if thats USD or AUD.
If I were supporting any Devs on Patreon I'd be annoyed at it taking so damned long for each release because I'd be paying way to much for what amounts to a picture book.
Fortunately I am not using Patreon.