Walk into a book store and look around. From different points in the bookstore count how many titles you can see. Which titles can you see entirely and which can you only see the spine of? Count them.
Now go to Amazon.com and perform the same experience. Count how many titles you can view at any given time. 10?
I buy and read a lot of books. What makes a good bookstore stand out is its selection. I want to be introduced to books that I would otherwise not know existed and frankly even with all of its algorithms Amazon sucks at this. I can walk into any bookstore and within 1 minute my eyes have scanned dozens of books. I take in their titles, size, color, binding, etc. All of this information impacts whether or not I will pick up a book to examine it further.
I enjoy the selection process and I want a bookstore that gives me that. My favorite bookstores have floor to ceiling shelves so that I can cover more ground quickly. There's no way you can reproduce this on a monitor, it's simply impossible.