Google any recipe, and there are at least 5 paragraphs (usually a lot more) of copy that no one will ever read, and isn't even meant for human consumption. Google "How to learn x", and you'll usually get copy written by people who know nothing about the subject, and maybe browsed Amazon for 30 minutes as research. Real, useful results that used to be the norm for Google are becoming more and more rare as time goes by…
> 17 U.S.C. 102(b): In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work.
So it's been a tradition in the recipe space for decades to include lots of descriptive "filler" text when you're writing your recipe book/blog. That filler text is copyrightable, which gives you legal recourse against people who might try to wholesale copy your work.
Of course, in the modern world, it's definitely true that they can also help with SEO. And honestly I wouldn't completely discount the idea of people actually reading them -- I know my wife has gone through phases where she has a couple different blogs bookmarked and will read through them to get ideas, but also because she liked the writing of the author.