Regarding Vegas, it doesnt seem like crosswalks are more efficient, especially from the perspective of the driver. 1) Large intersections with crosswalks tends to have people linger in the middle of the street. This delays the flow of traffic. 2) Right turns are much slower. 3) People who jaywalk. This can be easily observed in Vegas at major hotels. Cars are always struggling to turn into the hotel with large crowds of people trying to cross regardless of the color of the light.
That said, I agree with another poster that crosswalks are optimized to force you into hotels/shops and are subpar.
