I thought similarly about those books. But I was proven wrong after I read Scott Kelby's Lightroom book. The added value was understanding one author's workflow and also knowing what all features exist. Of course, one might say we can just google for all the features of Lightroom - but I personally never did that and book helped me learn all the superset of features. After that, I never referred to the book - I just google about specific things, now that I know what is out there.

There was once a discussion about reading programming books and similar point was made about learning on the go. One HN'er pointed out that reading end to end helps to know what all exists. It resonated strongly with me and since then, when I start on a new topic - I make sure to read at least one book end to end.