No, if you’re just looking for a one time sale. One book, one sale, and you’re done. You’ll never see that person again.
Yes, if you’d like to develop a relationship with ongoing customers who will buy your books (plural!) services, and other products.
A book is sometimes an impulse buy. It’s something someone might pick up after hearing a talk by the author, or at a bookstore, or another venue. Twenty bucks isn’t much of a commitment. But what if the book is a lead-in for a more expensive course or a consultation? You’ll want to stay in touch with that book buyer to broaden your relationship.
Maybe they’ll never buy another thing. But, maybe they’ll pass your emails on to someone else who becomes a client. Or, they’ll buy other expensive services down the line. Or, maybe they’ll become a friend and a cheerleader.
How should you use your mailing list?
Like you’ve been given a gift.
People have been gracious enough to invite you into their lives. Thank them by sending them good information – not just sales pitches.