To move so called "value", all you have to do is put a minus on the sending side and a plus on the receiving side..that's all there is to it.
No, that doesn't work. Eventually you wind up with a big positive number on one side and a big negative number someplace else. Then the guy with the big positive number needs to wire out money on a domestic payment system or some other rail, and he doesn't have any money in that other payment system.
If I want to send $10k from India to USA, its a 10k debit in India and a 10k credit in USA.
However you want to track that (using a token) doesnt mean you have to buy the token as well in order to "settle"
That doesn't actually settle. It just tracks debt. The entity that owes the money eventually has to settle the debt with some movement of actual value.
I could use R3 token to do the same thing as what you propose, without their being any sellable value of itself, outside its immediate function of tracking who is owed what
I don't see how that would work. Say I'm the only bank in the US that uses the R3 token. I have a billion of the R3 token with a value of one billion dollars US. Now one of my customers wants to make an ACH payment. What do I do?
Or say the US payment hub has way more R3 tokens than the Japan payment hub. Now what happens when people in the US payment hub want to move their dollars out of the payment hub? Where does it get the dollars from to cover?
You can use this as a single-currency payment system and as a way to net out opposite flows. But it still leaves you with a settlement problem. The case for a crypto-currency for global settlement is very strong. Of course, what fraction of that market XRP will be able to get is an open question, and it's Ripple's (the company) major focus.