Ripple is a great project but I'd like to understand better why Ripple currency (XRP) is needed there. As I see, the gateways use other existing currencies, either fiat (USD, EUR, etc) or crypto (BTC), and XRP is needed only if you want trade an exotic pair for which a market doesn't exist. Other than that, holding XRP gives no interest or dividends and it's not likely that XRP will be accepted by merchants even if the Ripple project succeeds. Am I missing something?