Sure. If someone took the time to write a book about what s/he thinks, and I don't mean teaching some subject (including their experiences in the subject), or writing some other fiction other non-fiction, but rather some semi-informed garbage providing only their opinion ("What I Think About ...", "Everything I Believe", or "My Autobiography"), then s/he is a substantial amount of time on a throwaway work. This is different than responding with opinion on HN, etc. because it isn't a discussion where they might actually engage someone else; it is a one-way conversation. Now if they wrote a wise work of art and is marketed correctly or widely popular, I might reconsider, but that probably isn't the case. I don't want someone who wrote a book like that and flaunting it in conversation working for me, because unless they are applying to a position as an editorialist, I don't want to read their diatribe emails or listen to soliloquies about their feelings on various subjects while at work, I want them to get their work done.

Why is a resume that shows understanding of the business important? Because it shows that they are focused on what is important to the work and relaying that information, rather than their opinion.