[jraph]

In many countries including mine, willingly putting work in the public domain is not possible.

In France, you have to wait 70 years and then the end of the year for your work to be in the public domain (sometimes, it's 70 years after the death of the author).

So you need a license like CC0 to "emulate" public domain, that does whatever is possible to give as many rights as possible to the extend permitted by law, in each jurisdiction. This is tricky, that's why CC0 is so long.

Public domain is just an area where the author cannot impose anything. If you can give all the possible rights that matter, it does not seem to really matter if you can't just put it in the public domain, or am I missing something?