You're absolutely right that money is merely information, but it's information about scarcity! After all, scarcity is the fundamental economic problem, i.e., the reason we need money in the first place. And that's why money needs to be scarce. If it's not, it can't accurately convey information about the underlying scarcity of real resources.
No, the idea that "money is merely information" is wrong to begin with. Trading with money is just a special case of barter which happens to involve highly-marketable commodities. Your net worth conveys information about your past balance between production and consumption; money is just one component, one which happens to be easier to account for than most, and more convenient for economic calculation. To be of any use, money has to be a marketable good, and anything which isn't scarce can't remain marketable, because no one would trade scarce goods for "money" anyone can get for free.
Note that Ripple doesn't eliminate the scarcity of money; not only does it have an even more restricted cap on the internal currency (XRP) than Bitcoin--the supply is not merely capped, but actually required to decrease over time--but the other currencies are limited by the participant's credit-worthiness, as measured in more conventional terms. In theory I could grant a trillion BTC of credit to a few of my closest friends, but no one would trust me to actually pay it back. In practice, the total credit actually traceable back to a trusted source, typically a gateway, will probably be limited to little more than the total amount on deposit with the gateways, or perhaps by the real-world property they can seize in the event of non-payment.
Ripple's problem isn't any lack of scarcity, but rather they it's trying to make a currency out of something non-fungible (loans with variable likelihood of default). Gateways mitigate this somewhat, by providing "trusted" centralized organizations with a low perceived risk of default, but if you have to rely on them for most trades you might as well employ the existing banking network.