I think that this is a visually interesting photo because it is a good representation of a close up shot. I enjoy looking at the detail of the chair and it makes it look more amazing then looking at the chair itself from a distance. I also like the curve line in the picture and I feel like the curve line is strong in the composition of the picture.
This is almost an extreme close up. I am not sure I would recognize this as a stool if I did not know the original object. It is also a good example of symmetry.