Stationary light will bake shadows on static objects and be dynamic on movable objects. Movable skylight cannot be baked and will only cast dynamic shadows (less realistic)
Assuming your house’s geometry is set to static. Stationary sky will have it’s lighting baked, movable skylight not. Movable skylight being 100% dynamic, doesn’t produce G.I (bounced lighting). That’s why the ceiling is pitch black. There is a settings on movable skylight that can ‘‘fake’’ a bounce of lighting tho, it’s to turn off the ‘‘lower hemisphere is a solid color’’ option :
In that scene the skylight is set to movable but I lowered the intensity quite a lot.
