The bottle of nail polish in the picture comes with a sample swatch attached to it. They did this so customers could see how the color actually looks on nails before buying the bottle. This was super clever, and adding this sample definitely helped them sell a lot more bottles. Seeing how the color would look before purchasing can also help shoppers save some money.
The thing about buying nail polish is that it might look great in the bottle, but something completely different could show up on your nails; this is why this brand is perfect.