This is just my take on the shelti photo, but I think the tower in the background adds balance. Without it there, the photograph becomes too open -- there's a dog, and too much empty space around it. With the tower, there's a dog (the subject, the thing we're supposed to look at and admire) lower left, more or less, and then a second object (less interesting, not the subject, nothing we're really supposed to look at, really) more or less upper right. It doesn't distract from the dog, but I feel that it gives some "visual weight" to that otherwise too-empty region.
This is definitely getting in to territory that's more about opinion and feeling than hard facts, so others may disagree.