The purpose of this rim is to shift the spokes to centre them between the hub flanges. By using an asymmetrical rim, the angles are reduced and therefore the difference in spoke tension and length on both sides of the rim is reduced.
It has several advantages:
Balancing the spoke tension ensures that the wheel will last for a long time. Also, the spokes will more easily keep their original tension. Indeed, on a classic rim, the difference in angle formed by the spokes on the drive side and on the disc side, forces to adapt their tension so that the rim remains centred.
This allows the chain to have more passage without the risk of touching the spokes (on the sprocket side, especially on a 12-speed cassette)