Have you ever tried to install a set of shelves only to find that the brackets get in the way? No matter how you change it around, you just cant seem to get it right. There is a type of shelving that can help you avoid this problem altogether, they are called floating shelves.
With standing structures, there is much more room for uniqueness. They have a large base upon which there is plenty of room to decorate. They also leave room on tabletops so that the decorator has more surfaces to work with for picture frames and trinkets. There is also not the burden of worrying if a table is sturdy enough to support the decoration.