Savings start with all non-essential things first.

According to the source linked in the top comment, we are looking at a total consumption of 113.000 MWh per year for those displays. One third of that is at least around 30.000 MWh of saved energy.

So 0.005% at 560 TWh total consumption.

Well, in that case we shouldn't improve anything as long as children are starving to death in this world. That should be our only and biggest "bug" to fix. Feel free to recommend another one, but we'll pause all other improvements meanwhile. ¯\_(ツ)_/¯

How about not jeopardizing the economy by ever more constraints and instead investing in better energy technology?

Maine banned all billboard style advertising decades ago. Our economy functions just fine thank you.

The action is super visible though. Sometimes that's the most important thing. /s