I wish it were called something different. I know that might sound a bit petty, but we frequently have discussions here where a "Creative Commons" licence is used to describe a copyright situation where *some* legal rights are retained, and it's just down to the exact licence as to what's kept and what's freed. (Which is in comparison to a "Commercial Copyright" -- the standard / default thing under one's own country's law.)
Having to explain "Creative Commons Public Domain" is just going to be messy. Since the ENTIRE legal spiel reads:
The person who has associated a work with this document (the "Work") asserts that he or she (the "Asserter") has taken reasonable steps to verify the copyright status of the Work under US law.
The Asserter hereby asserts that to the best of her or his knowledge, there are no copyrights in connection with the Work (the "Assertion").
The Asserter understands and acknowledges that her or his good faith efforts to verify the copyright status of the Work may not shield the Asserter from claims of liability arising from the Assertion.
The Asserter understands and acknowledges that Creative Commons is not a party to the Assertion and has no duty or obligation with respect to the Assertion or use of the Work.
which can be summarised to:
The person who has associated a work with this document hereby asserts that there are no copyright interests in the work.
... why not just call it Public Domain and have done with it.
That's my own LV-ish view. Overall, it's pretty cool that they're adding a restriction-free option and I hope it's taken up enthusiastically.