But a crypto currency that doesn't need trust is even better.
It is impossible to remove trust requirements from
all types of transactions. For example, ordering a product online. What if they don't ship? Crypto-currncies do a great job of reducing the amount of trust that we need but I don't think it can be eliminated completely.
For example, there's no way to trade with leverage on Ripple. In fact in the Ripple wiki they give plenty of reasons why an off-ledger exchange can be superior to Ripple's built in exchange.
Interesting point. Escrow would help with the case of ordering a product, but in general you do need trust, that's true. And lending is an important economic function, and that involves a great amount of trust as well as due diligence to make sure that trust is warranted, collateral etc. But that said, cryptocurrencies eliminate some counterparty risk, which is a good thing, and an advantage over systems that require more trust.