You might wonder why you would ever give up monetized YouTube with thousands of subscribers. However, there are a lot of good reasons to give your YouTube account to someone else.
Motives personal: Whether you've encountered a huge life altering event or grown out of your YouTube account, you might wish to sell for individual reasons. After all, maintaining video content takes a lot of time and effort.
Future open doors: If you've taken your digital entrepreneurship to other parts of the internet, you might want to sell and invest in new business ventures.
YouTube is more difficult to sell in some ways than other digital properties like blogs or eCommerce stores. Having said that, it is doable and might be the next step for your channel that has been monetized.