You may be right, in terms of the present developers' intent, although I think the system has quite a ways to go before lots of people will be using it for payments.  Except for Bitcoin users (who don't really need Ripple for transfers since they could just send Bitcoins directly), getting real money into and out of a gateway like Bitstamp is still a bit cumbersome - mainly because it seems that getting US dollars into or out of a traditional bank (where most people still keep most of their money) still always takes several days.  Although money-orders from retail stores (CVS, etc.) through BitInstant are faster, they have relatively high fees. 

So ultimately, to speed up/cheapen the money-transfer process, we need to get away from using traditional banks entirely.  It will be a long time before most people can do that.  And for it to be possible, the use of systems like Ripple needs to grow so there is more credit available through it.  Using Ripple for exchanging IOUs (as originally envisioned) is one way that anyone can begin to use it quickly and easily to facilitate day-to-day financial interactions with friends/clients without having to wait for any slow, cumbersome bank transactions to clear, or pay for expensive wire transfers or money orders to get money quickly to a Ripple gateway.