Quite some time ago, I signed up for Quora. It was an impulse thing because I got an invite from a friend. Every so often, I scan through my emails from them and look for questions that interest me, or things that friends have written. Up until today, I’ve never felt the impulse to sit down and type out an answer.
Then I saw the question, “Why do bookstores have reading areas?” That’s a question that I pondered occasionally back in the days when I hung out in bookstores but didn’t own one. It became more pertinent when Kathy and I bought a bookshop. So I wrote an answer:
When I bought my bookstore more than 13 years ago, it was tiny. The whole store fit in less than 500 square feet, yet the previous owners had made room for two well-worn but comfortable armchairs. Over the years that I’ve owned the store, the amount of seating has ebbed and flowed: couches have come and gone, we’ve had wicker chairs, benches, and stools. Today, we still have those two threadbare armchairs.
The reason is simple: if people can sit down and look through the books, they will stay in the store longer and they will buy more books. Why do people shop in physical bookstores in 2014? Because they want to interact with physical books and talk to book lovers. They want to heft the books. They want to compare similar books to decide which one(s) they want. And every study says that the longer they shop, the more they buy.

As Drew mentioned in his answer, stores want to be the “third place” in your life after home and work. That’s why we have a tea bar and many other bookstores have coffee shops. That’s why we have game nights. That’s why bookstores love to host book clubs. That’s why bookstores bring in authors for signings and talks. We want to offer something that a website can’t offer, and we want to provide a comfortable place to do it.
The optimum amount of space is a fluid thing. If our seating areas are all filled all the time, we add more. If there are empty chairs around the store all day, we replace them with tables or shelves filled with products. I don’t think there’s a single answer to that part of the question.
Free riders? In the years I’ve owned the store, I doubt if there has been a single person that’s read an entire book in my store without buying it. In contrast, quite a few people have picked up a book, spent an hour browsing it, and ended up buying that book. And then coming back for another book by that author. And another. And another.
TL,DR version of the answer: we offer reading space because it makes our customers happy and helps us to sell books.
Sometimes, people just want to get out of the house for a while. We hope they’ll want to do it in our store.