It's very unclear how it works around the world in different legal systems. In comparison the CC0 spends a lot of words to work with all the jurisdictions where

It's very unclear how it works around the world in different legal systems. In comparison the CC0 spends a lot of words to work with all the jurisdictions where you can't legally give up all rights over a work. If you are operating internationally (like nearly the entire tech industry), complying in as many jurisdictions as possible is very valuable