Yes, exactly. Sometimes access to high resolution scans of the material is included with purchase (I recall the Taschen books on the history of typefaces and th

Yes, exactly. Sometimes access to high resolution scans of the material is included with purchase (I recall the Taschen books on the history of typefaces and the Modernist Cuisine set offering some form of this), but not nearly often enough. A lot of books are also simply unavailable as ebooks (like Bertin's Semiology of Graphics).