If used as an intermediary unit on the IOV within ILP, couldn't the governments, central banks, and private banks using it to transfer assets agree to a value for each XRP...speculators and traders be damned?
For instance Bank A wants to send 20 billion yuan to Bank B who wants it in dollars. The network "agrees" that each XRP is worth $1000 so Bank A "sends" the at-the-moment equivalent of said-dollars (yuan) through the IOV via ILP and it comes out on the other side as dollars.
In this example, the value of the XRP used is needed in order for the XRP blockchain to record the amount utilized to perform this transaction. It actually wouldn't matter if the value of each was $0.50 or $10,000...you'll either use a lot of them to move your $$ or relatively few of them.