Different material thickness
Disposable bathrobes are made of thick and heavy materials while dressing gowns materials could be softer and lighter weight.
Design
Disposable bathrobes have a pretty basic and plain design, while dressing gowns may have intricate designs.
Usually, disposable bathrobes are loose-fitting outer garments worn by both men and women while dressing gowns are long and loose robes or coats worn inside the house.
Different wearing purpose
Bathrobes are worn after taking a shower while dressing gowns can be anytime while in the house.
Different function request
Disposable bathrobes should have water absorb function, while dressing gowns no need to be water-absorbent.
Basically, both bathrobes and dressing gowns are garments for casual relaxation. Bathrobes are more commonly used than dressing gowns. Bathrobes are made from thicker, and absorbent materials while dressing gowns are not, most dressing gowns are cotton, or silk materials which are reusable and washable. Thus, this is the main difference between bathrobe and dressing gown.