There can be a backsplash (sidesplash ?) on the left. I would say it would look better. But your countertop has contoured edge, and I don't see how the sidesplash is going to work out with that countertop. Was the countertop manufactured and installed separately from the vanity, or was the vanity and countertop (and possibly sink) purchased as all one part number ?
That gap between the wall and the cabinets makes me think that vanity was not intended to be placed against a wall --- more appropriate, for example, in the center of a long wall, with a few feet empty on either side.