I'm going to copy this comment I saw on slashdot re: this yesterday that seemed to let some of the air out of the whole press release:
"The salt mentioned is not table salt, but lithium chloride.
Lithium chloride - which makes up a half by weight of the film, and is also in obvious demand for batteries, is $70/kg or so in bulk."
I haven't really dug in deep myself, but this is the comment that deflated me when reading about this yesterday, so worth looking into at least imo
Doesn't seem like this would be used for agriculture at scale - but it sure could beat digging a well to get water for a house.