I think evaporating large areas of salt water could increase the local air moisture level substantially. That with the passive desalination could make water much cheaper in coastal areas.
It's also worth asking how desalination can be used in say afforestation or ecosystem restoration, to improve evapotranspiration of water over a landscape where appropriate.
I recall the CEO of terraformation (Yishan Wong) talking about using desal with brackish wells : https://www.terraformation.com/blog/solar-powered-desalinati...