Your chosen font should invoke the messaging of the book and how you want the reader to feel while immersed in the writing. The right font is something the reader may not even notice because it flows so well with the content, whereas the wrong font can seem awkward and out of place, creating a jarring reading experience.
It was the ’80s, and desktop publishing was just starting to take off. Bringhurst felt the sudden availability of digital fonts would overwhelm any inclination toward rational design and cause typographical chaos. He did what any perfectionist would do: write a book.