Israel turned over Gaza precisely so there would be an enemy entity to declare against. When Gaza was Israeli, there could be no such declaration, just more Israeli collateral damage when the military attacked Hamas.
I don’t think it will ultimately be a successful gambit, but there is logic in having a geographically defined enemy entity.
I don’t see the usefulness in handing Gaza over to have a defined enemy, if Israel acts like the wimp parents who need “Supernanny”. Here’s a rhetorical question for you: Why are they “thinking about” turning the power off? Let Hamas figure out how to generate electricity. Then they may regret forcing their smart people (moderates) to run to the US. Enough already with these millions of people who refuse to develop their own economy! Cut their electricity now!