“What’s the harm?” is just turning the question around because the original question — “what’s the benefit?” — doesn’t have a satisfying answer. If you want to

“What’s the harm?” is just turning the question around because the original question — “what’s the benefit?” — doesn’t have a satisfying answer. If you want to reduce it down to “LFLs make people with extra books feel good” then, great, it’s obviously a resounding success, as evidenced by all the articles of people who built them beaming.