from an article on xrp-
But not all the transactions that banks make on the Ripple platform have to use the XRP tokens, as was pointed out by The New York Times. Instead, banks could use dollars, euros, or another local currency on the Ripple platform, circumventing the alt-coin.
This cuts into what some buyers of XRP hope: that it can become a bridge currency used by financial institutions to make payments across borders.
In other words, as investors come to realize that Ripple the company does not need XRP the token to soar in price to be successful, investors may further cool to XRP.
That's almost the same as Ethereum, to be honest, with the exception that even if you circumvent using Eth to transfer tokens, you still need to pay miners gas (or spend ether) to spend all those ERC20 tokens. Yes, it creates a small micro economy where Ether is being used, but as all of this goes to miners, you might argue that the same net effect can be observed. But hey, it still increases Eth's value. They have to develop and improve the platform. And if XRP does the same, the token itself will experience the same slower rise.