All the other reasons like spam notwithstanding, without at least some persistent user ID, how would image licensing work? You'd only be able to have works that

All the other reasons like spam notwithstanding, without at least some persistent user ID, how would image licensing work? You'd only be able to have works that can be shared and modified freely without attribution. Wikimedia is surprisingly lenient on accounts, you don't even need to give an email to get a username.