Practical and sturdy, or more decorative?

I have my books on some of the tall bookshelves, I order and install an extra shelf, on rugs I buy wooden wedges about an inch and a half wide, seven and a half inches long, I put these under the sides flush with the front to get the bookcase to lean back against the wall instead of using the included single metal bracket to secure it to the wall as most walls are not substantial enough to hold the included single metal bracket