Dads , why cant we open the lights inside the car?

Not a dad, but it fucks up night vision. Your pupils expand and contract based on how much light is in an area, which allows them to get more or less light respectively. Turning on lights in the car is like getting hit by highbeams. It forces your pupils to rapidly contract. They take longer to fully expand than contract, which means for the next bit of time, your vision at night is limited as your pupils are partially contracted, filtering out light. In low light conditions you need all the light you can get. Essentially your eyes are light powered vacuums and the vacuum gets stronger the less light there is, but takes a bit to get there. So when light hits it hard, you're gonna be partially blinded for a bit. Furthermore, it's hard to see out a window to the dark in the light.