The two small drawer boxes standing on the top, one either side of the mirror, are older than they look. They are the descendants of glove boxes - little cases that sat on a dressing table to hold gloves, hairpins, rings and the small things a person reached for last before leaving a room.
They survive because of where they are rather than what they hold. A drawer set into the frieze of a table is below the top, which means reaching down and, if you are seated, leaning. A box standing on the top puts its drawer at the same height as your hands already are while you are dressing. The difference is a few inches and it is the difference between a drawer you use every day and one you forget about.
Building them separately rather than as part of the top is deliberate too. Each box is its own small case with its own jointed drawer, set onto the finished top, so the top stays a continuous unbroken surface underneath. That matters when something spills - there is no seam for liquid to run into.
It also means they can be positioned. Move them outward and the mirror gets more room; move them inward and the top gets clearer at the ends. On a made-to-order piece that is your decision rather than the design's.