Not sure what you mean by offset, since the study doesn't make any value judgments about city size, etc, but just identifies the effect cities may have on precipitation. The authors have expertise to help cities adapt to extremes, and suggest that planners consider those effects.

The offset of cities being more efficient in terms of resource usage, which some stidies have shown, versus the impacts of them making nearby regions dryer as in this study. I dont know if one outweighs the other, the offset, or not. I saw a few people just saying "see cities bad" in quote tweets.