I'm much more of a fan of fiction, but I do enjoy some interesting nonfiction here and there.

What you have to understand is that "nonfiction" is a huge umbrella category. It's not "just feeding you knowledge." I mean, textbooks are technically nonfiction as well I guess, but there are plenty of plot-driven novels whose content is written to be as historically accurate as possible. If you go in without the attitude of "I'm here to learn about history," it'll be no different from any other novel. Except, at the end of the day, the things you read are real, and regardless of your intent, you learned something just by enjoying it. Killers of the Flower Moon is about to be a Scorsese film, and you wouldn't skip out on that just because the story is true, right? Why would you treat the book any differently? (Of course, I'm sure they'll take some liberties adapting it to the screen...)

And you can learn from fiction as well. Setting aside language skills, plenty of fiction will have asides—or even core plot points—exploring the very real history of things their characters interact with. Visiting a real place, getting excited talking about their hobbies, fighting a villain whose dastardly plot is built on actual science, or just hard sci-fi in general. And those tidbits within fiction aren't moments of boredom. They flesh out the story and make it more believable!

So some nonfiction books focus in on that, filling the every page with those interesting asides, organized around a central theme. You don't need a traditional plot linking them together; it's just a collection of interesting information. And you found it interesting when it interrupted the plot of a fictional story, so why would it be any less interesting when you read it in What If? Why would it change when those interesting facts are linked around a central theme, like in The Design of Everyday Things? Or when they follow a "plot" that doesn't focus on characters, like in Glock: The Rise of America's Gun?