Let's face it: lights are a minor annoyance that are juuuust inconvenient enough that we want lights, but not inconvenient enough that we actually bother placing them.

So, now lack of lights reduce total average production by ~40% (or however long night is).

As a bonus, it now makes it far easier to selectively ease off on battery/coal plants - if you want to run daytime-only assemblers and just buffer the output for night-time, you don't have to run an entirely separate grid or futz around with circuits, you just neglect to place the light on that assembly line!

And before you research optics, you can only operate your assemblers during the day! Better hurry!