Dhālat and adhyāl have a noticeable echo of sound as well as connected senses. Dhayl is the hem or trailing part of a garment, and adhyāl its plural. Saḥl refers here to white cloth; mumaddad means extended or spread out.
The poet creates a visible picture of the gait through moving cloth and long trailing edges. The point is kinetic resemblance, not any claim about the garment’s monetary value or the social ethics of the scene.