Combining the bedroom and bathroom can save space because the bathroom doesn't need its own. Frosted glass, sliding panels, or simple antique dividers can provide some sense of privacy while in the bathroom. You can also allocate a smaller space for the bathroom in the integration since it won't factor in the walls (as there aren't any). In addition, the bathroom can share lighting with the bedroom and help you save on energy costs.
However, this design doesn't make sense for small bedrooms; you want to have some elbow room between the bed and bath. In addition, you need to factor in the water; will the design spill water in the bedroom? This design isn't entirely open since there's still the matter of privacy and water damage to take into consideration. Get a bathroom remodeling contractor to discuss this design as to whether or not it's feasible for your home.