Many experienced photographers say that the shallow depth of field is an excellent way to highlight an interesting part of the composition. It may not be the type of technique you want to use when shooting technical objects, but when you want to highlight a part of a photo, the depth of field is fantastic. Composition is one of the easiest techniques to use to improve your images, and it's also one of the most overlooked. You might never think about it, but maybe you should.
Your composition can strengthen a mediocre image just by moving the camera. Layering is especially effective when there is a noticeable contrast in the tone or texture of two overlapping objects. This contrast helps separate objects from each other. Take a couple of pictures and you'll see that this technique actually increases the emphasis of the product itself.
The concept is often used in product photography to emphasize and even embellish a product to make it more interesting. You never know when you're going to meet a new customer who is interested in photographing their products in this way. One of the dangers of working with DOF for product photographers is that you start to rely too much on the technique. Depth of field is a fantastic and versatile way to photograph anything from products to landscapes.