ZCash's "trusted setup" is a liability. 6 people controlled (control?) shards of the SNARK private key. The idea is if any one or more of those shards were destroyed, then the key is successfully obfuscated. But, there is no way to know if those shards were destroyed. And there is no way they can ever prove it. So, if those 6 people are colluding, then they can inflate the currency at will using that key and no one would ever be able to know. Moreover, even if those people were honest and destroyed their shards, it's possible that the shards were compromised by another party who now controls them all, and thus, the private key.
So, for a currency that is supposed to be 100% trustworthy in all aspects, it is built upon a foundation of trust in a very small number of central people who have a huge incentive to be dishonest (they can "print" as much ZCash as they want if they retain the SNARK public parameters private key without anyone knowing).
Furthmore, ZCash isn't the first anonymous coin. Monero (XMR) has been out for a long time and requires no trust and is completely anonymous.