[legutierr]

The blockchain data structure makes the data it encodes tamper-proof. It makes historical data immutable, and it makes the current state of a system and the state transitions that led to the current state fully auditable in a shared-data context. These features enable applications that might otherwise incentivize illicit data tampering (such as applications that deal with asset account balances and ownership records) to be decentralized. I am unaware of another solution to this particular problem.

"Zero trust" is meant to refer to the data layer: because the current state of a blockchain system can be re-generated deterministically from the historical data—which is immutable and fully auditable—you don't have to trust anyone's version of the current system state, even if you are not yourself currently keeping a copy of it.

These technologies do not solve all of the moral and ethical problems that humanity faces, but I don't think anyone is claiming that they do. Blockchains don't stop people from deceiving each other, and they don't make people smarter so that they entirely avoid introducing bugs into their software, and they don't stop people from trying to steal from one another.

But they do make it possible to decentralize high-value data records that would otherwise need to live in high-security environments controlled by governments or well-capitalized businesses that would also need to be trusted 100% not to tamper with those records.