Unlike light bulbs, which are dark-suckers and which wear out their lighting abilities as they get full (hence the dark spots on burnt-out light bulbs); black holes are light suckers which gather and consolidate light from many sources and they get stronger at lighting things up as they get fuller. The dynamics are different - similar to how air conditioners also create heat which must be vented to the outside and how we can use a flame from propane to make a refrigerator cold.
I’ve heard that dark is heavier than light and that is why it sinks to the bottom of the ocean.