Private coins betrayal the initial approach of Satoshi Nakamoto paper about transparency. Which is the main difference between the digital currency and Fiat.
Betrayal of the principles of the mother of all cryptocurrencies, our beloved Bitcoin. This is like betraying your own parents.
You mighty disagree but that what it is. I do not see it as an improvement but rather a lack of integrity.
Prevention from hostile environments?
Well Bitcoin has the value it has today within the so called hostile environments. Sorry, too much paranoia, which is a kind of mental illness.
Somehow the blockchain as open as it is , aloud this kind of project like Zen Cash to be released.
Charlie Lee the founder of Litecoin admits that without Bitcoin, Litecoin would not exist, now he also talks about privacy. Why? Simple. He wants to avoid people to see his high earnings & transactions like many others. Is it the beginning of the end?