Ripple is a debt accounting system.
You can send Dollars or gold over Ripple - you can transfer promissory nodes for those things.
The difference between a promissory note and the value the note represents is something that Ripple should be trying to clarify - instead they seek to obscure it.
Because they try to pretend that promissory notes are equal to underlying assets, they don't include any features that would act like leverage limits. There is no ability to deal with counterparty risk rationally in their system, since trust in a counterpary is binary.
In real world, liabilities of different entities are discounted by a value that reflects their credit risk. Ripple does not permit this operation. You either value liabilities at par or not at all.
As others have mentioned, their consensus system is neither distributed nor trustless. It's a centralized, badly-designed, debt accounting system trying to pretend it's a trustless cryptocurrency.