What's the functional difference? It's a way of combining assets then removing them such that tracing becomes difficult/impossible. The link I gave warns about hiding transactions over $10k, as I understand it doing that with zerocoin would be illegal.
I agree, we need to make bitcoin even better before releasing it and see it fail because anonymity is currently not part of it, though people still claim it is.
Zerocoin and whatnot!
If a government declares all anonymous digital money to be dirty by default then technologies like CoinJoin or Zerocoin just make everyone who uses them into criminals. If people want to successfully move money between the dark and light economies they need technology that creates a plausible audit trail... but pointing in the wrong direction. I don't know if that is even possible.
http://blog.cryptographyengineering.com/2013/04/zerocoin-mak...
http://zerocoin.org/