You’re much better off with the plants.
First, the plants’ roots improve the permeability of the soil. They provide thousands of channels for the water to work its way down. Having plants there will also encourage the presence of earthworms, which will provide yet more permeability.
Second, the water is drawn up into the plants’ leaves, where it’s more available for evaporation (through the process of transpiration )than if it were down in the soil. Think about it: All of that leaf surface area is probably thousands of times greater than the surface area of the soil itself. When the sun is shining on that patch, or when the air circulates over it, that’s that much more surface area from which evaporation can occur.