But this is good not bad because that is exactly what bitcoin needs. This will improve the economics of bitcoin as a monetary system. Current situation is unsustainable. Every service that is offered for free sooner or later will be abused in every imaginable way. This is exactly what is happening now and "spam" on the blockchain is increasing. Customers have to compete for space in the blockchain!
Situation would get much worse if Zerocoin was implemented in it's current form. The scalability would get worse, not better. Customers would compete much more for space in blockchain, not less, because all the space would be taken by only a few zerocoin transactions.
Real zerocoin transactions just can't be used inside the blockchain in their current form.
People should either read the paper carefully or read it's analysis by others who understand it before making these comments about zerocoin being awesome and bashing on the bitcoin devs for not including it.
I'm not sure why people are so afraid when money laundering is mentioned? If you are NOT a criminal money laundering is NOT a crime!
If you are not a criminal, it's not called money laundering. If all your money sources are legit and taxed, you can't or will want to launder the money, you will just use it and nobody will have any problems with it. Earning money and not paying tax on it, while still living in the country that needs those taxes and using the services it provides for those taxes is a crime though.