No, it is. Those already exist in the form of Monero. Using some new-fangled, likely broken cryptography, is very hipster.

IMHO the biggest privacy-breaking problem of Monero is that it leaks the transaction amounts, while Zcash does not. Monero also has other inconvenients compared to Zcash: https://www.reddit.com/r/Monero/comments/41vg68/monero_vs_zc...

So you can't claim Monero already solved all the problems that Zcash is trying to solve.

That's incorrect, Monero does not leak amounts since they created and added RingCT (currently compulsory on testnet, and compulsory on mainnet from a hard fork next year September) - https://lab.getmonero.org/pubs/MRL-0005.pdf

Not only does Monero already do what ZCash is trying to do, but it has two main advantages:

1. EVERY transaction is private, which means that the entropy of the anonymityset is continuously growing. Instead, ZCash restricts privacy to an opt-in mechanism (mostly due to private transactions being horrible - requiring north of 8gb of RAM and several minutes on a modern computer) which means that there is a trivial amount of entropy, and deanonymization is pretty trivial.

2. Monero is focusing on further improvements that ZCash is just dreaming about, such as their C++ i2p router, Kovri. They can do this because they've been in production, tested, and hammered for several years.

The real question is: what does ZCash provide that Monero doesn't, except some sort of ridiculous "star cred"?

Monero doesn't already do what Zcash is doing. As you point out yourself, it will be "next year September" that RingCT will be live.

I agree with your other criticism of Zcash though. The situation is far from perfect.

No, it'll be MANDATORY from next year September, not LIVE from next year September...