Not that Google has done anything to make it more obvious but ChromeOS, the OS on GoogleBooks, and an obscure Linux you can put on random old PCs, are all related in interesting ways if not derived from the same project.

The practical issue in this case appears to be that GoogleBooks branding is meant to indicate they are good at running Gemini and other Google AI technologies. Chromebook aren't.

I doubt the entity called Google is of one mind about any of this.