I know, but it's also very far from zero and people might have most of their lights on for quite a few hours. ~200W for 4-6 hours every day for almost every ho

I know, but it's also very far from zero and people might have most of their lights on for quite a few hours. ~200W for 4-6 hours every day for almost every household in a country is a huge number, and that's with the assumption that they're all LED. Its also not orders of magnitude form AC usage: If small 800W AC runs at 50% duty cycle for a similar number of hours, the light is approx half the AC consumption. Turning off light you don't need will absolutely make a difference.