Wiki:
Use as a payment/forex system
Ripple allows users or businesses to conduct cross-currency transactions in 3 to 5 seconds. All accounts and transactions are cryptographically secure and algorithmically verified. Payments can only be authorized by the account holder and all payments are processed automatically without any third parties or intermediaries. Ripple validates accounts and balances instantly for payment transmission and delivers payment notification with very little latency (within a few seconds). Payments are irreversible, and there are no chargebacks. XRP cannot be frozen or seized. While as of 2014 anyone could open an account on Ripple, by 2015 identity verification procedures had been implemented. Ripple's Path-finding Algorithm searches for the fastest, cheapest path between two currencies. In the case of a user who wants to send a payment from USD to EUR, this could be a "one-hop" path directly from USD to EUR, or it could be a multi-hop path, perhaps from USD to CAD to XRP to EUR. Path finding is designed to seek out the cheapest conversion cost for the user. As of May 14, 2014, Ripple's gateways allow deposits in a limited number of fiat currencies (USD, EUR, MXN, NZD, GBP, NOK, JPY, CAD, CHF, CNY, AUD), a handful of crypto currencies (BTC, XRP, LTC, NMC, NXT, PPC, XVN, SLL) and a few commodities (gold, silver, platinum).
The Bitcoin Bridge
The bitcoin bridge is a link between the Ripple and bitcoin ecosystems. The bridge makes it possible to pay any bitcoin user straight from a Ripple account without ever needing to hold any of the digital currency. Additionally, any merchant accepting bitcoins has the potential to accept any currency in the world. For example, a Ripple user may prefer to keep money in USD and not own bitcoins. A merchant, however, may desire payment in bitcoin. The bitcoin bridge allows any Ripple user to send bitcoins without having to use a central exchange such as BTC-e to acquire them. Bitstamp acts as a gateway for the Ripple payment protocol, among other exchanges.