Why Do We Dream? Maybe to Ensure We Can Literally 'See' the World upon Awakening

A theory holds that dreams are a way for the visual cortex of the brain to “defend its turf” against being “taken over” to process inputs from other senses

https://www.scientificamerican.com/article/why-do-we-dream-maybe-to-ensure-we-can-literally-see-the-world-upon-awakening/