Mold is considered a plant. Mold might be a very small plant, but it still falls in that category. Therefore, if you decided not to remove the mold from surfaces in your building then it would leave a rough surface and you would roll the fungal growth over a larger area.
Painting over it doesn't remove the mold. You would first want to address the cause of the mold growth to stop it from happening again. Then the next step would be mold mitigation. This means that the mold would be physically removed and the surface treated and dried.
Once those steps in the mold damage restoration process are complete then you can repaint the area.