There's a general attitude to some of the comments here. "Another altcoin." "I wouldn't weigh the odds that this specific system really lasting more than 4 years out especially high." ZCash isn't just another fly-by-night cryptocurrency scam. It's a serious engineering effort that was carefully undertaken by some very well-known cryptography and security experts. Matthew Green Daira Hopwood Taylor Hornby Ian Meiers Z…
I was one of the first and most dismissive when bitcoin was released. I'm on record saying "yet another p2p currency piece of crap" one ~day after its January 2009 announcement and release. There are so many endless p2p currencies out there-- this was even the case when bitcoin was first launched-- so many that, frankly, any dismissive attitude is completely justified. You can't go around saying "you're too dismissive" because by doing so you commit the same crime you're accusing others of committing. Keep in mind that for some of us there's a lot of background in reviewing cryptocurrency proposals; it came as surprise to me to later learn that there was actual working source code associated with bitcoin rather than merely manifesto emails.
Also, "I wouldn't weigh the odds that this specific system really lasting more than 4 years out especially high" is clearly a reference to the author's experience analyzing (or reviewing) zk-SNARKs and related cryptocurrency proposals. I suspect even Zooko would readily admit that there are alternative SNARKs constructions that they might move towards over time. Heck, it was nullc who pointed out to me that Bryan Parno had published on a libsnark security hole: https://eprint.iacr.org/2015/437 -- and besides, it's not yet time to say that the trusted setup and the host of new cryptographic assumptions are rock solid... otherwise let's merge this into bitcoin. "Attitude", ha.
Also... it's not clear whether a high-privacy cryptocurrency, built by a specific nameable centralized company, is able to both operate as a legal business entity while still ensuring they are not operating under secret court orders from secret courts or other adversarial government interests, such as to inject silent inflation or otherwise compromise your integrity. It's too early to dismiss the concerns (of adversarial intervention) regarding the financial link between the Zcash developers and the Zcash cryptocurrency. (It may not be clear to casual readers that, unlike in Zcash, in bitcoinland there's no protocol rules about paying developers from the mining subsidy reward amounts. There are very strong reasons for why this is still the case.)
(If you are going to have adversarial intervention like that, then you might as well use a much more directly centralized currency. It's not enough to handwave about the wonders of crypto and theoretical computer science while subjecting your work to extreme adversarial intervention. High-privacy designs in a centralized system can somewhat work, even if you were to want to explicitly make a backdoor for whatever law enforcement interests you pledge loyalty to.)