Probably another marketing ploy. In a market that is increasingly saturated they need to define themselves.
You could say wouldnt this be only useful for homebrewers and not the general public. But this kind of thing would be a perfect coffee table book. You only have to look at the amount of cookbooks that are bought and never used. This is the kind of book would be bought as a present, flicked through by the reciepent and then never opened again. Give it a few months and you'll be able to pick them up at charity shops for a few quid