https://www.nytimes.com/2020/08/26/magazine/sex-offender-operation-net-nanny.html
I finally got around to reading the source story that I linked above. After the guy said "...do you mean 23?" the article says "Was this an elaborate game? Again she claimed to be 13." The suspect had a bench trial and upon conviction the judges remarks included “the defendant clearly expressed by words and conduct that he intended to have sex with a 13-year-old.”
The word "dividends" has been misinterpreted by both you and the article you quote in the op. The whole quote in context is "Considering the high level of potential offense, there is a meager investment that pays huge dividends." In this context "dividends" refers to preventing a predator from harming a victim.
Law enforcement can be reactive or proactive. Operations such as these are attempts to be proactive, so of course there is no real "victim". Weather or not these type of operations actually prevent crime is a fine discussion to have.