> They are not a significant food source for other animals

In Indonesia for one they are. Every night, countless geckos come out, both indoors and outdoors, and start hunting for mosquitoes. Even lullabies sing about it [1].

The above song is so popular that it got an AI parody [2].

I'm curious what food chain reaction this will start if successful.

[1]: https://youtu.be/dOhHiwWwXFw

[2]: https://youtu.be/c6Ad8WAigdQ

What's the worst that can happen?

  The extermination of sparrows – also known as the Eliminate Sparrows campaign – resulted in severe ecological imbalance, and was one of the causes of the Great Chinese Famine which lasted from 1959 to 1961, with an estimated death toll due to starvation ranging in the tens of millions (15 to 55 million).
https://en.wikipedia.org/wiki/Four_Pests_campaign

Though that's unlikely to follow on from simply reducing mosquitoes in urban areas ... it absolutely warrants a close eye being kept on roll out and knock on effects.