This particular one is only mildly effective; precooling can lower later demand somewhat.

My house is very well insulated, but I still cannot coast from 5:30pm to 9:30pm (when windows are sufficient for comfort and demand really starts to slope off) without an excessive amount of prechilling. My structure, insulation, and attic are all preheated by the day's heat and so there is a big warm thermal mass next to my living space.

Also, opening windows overnight increases indoor humidity, which in turn requires more air conditioning the next day.

If it'll save you 10% on your electric bill, would you do it? I would. And reducing peak demand by 10% can really reduce the cost and need for grid battery storage.

Best of all, doing this sort of management of your HVAC system costs you essentially nothing. It's picking money off the ground.