On the surface we're trying to get moisture in the air rapidly(humidity). However, in actualality the droplets are too big and fall downward. It may give a very short term effect who knows, maybe a study should be done.
On the flip side, spraying does a better job covering a the substrate for hydration over pouring. And that WILL work better than just pouring to humidify because you have your water more evenly thinned and spread out.
I do both, pour and spray, that way I'm using both, short term and long term treatment.