Decorative lighting. This adds visual sparkle. Whitehead advises using a single pendant in a square-shaped bathroom for just the right touch.
All-around lighting includes general lighting and natural light. You want to ensure that at any time of day there is enough light for everyone to effectively use the space without incident and that any dark areas are minimized.
However a grid of pot lights is not all you need for a balanced light scheme. Notice that this space also includes a pendant sconces and art lamps (more on those later) as well as a full wall of windows. Including at least three layers of light from different categories and in different locations eliminates strong shadows and adds a sense of sparkle that allows all the other furnishings to look their best.