There's just one problem, the banking world already has a platform (created by the banks) called Swift.
Nearly every bank in the world is signed up to this platform and the banks can send payment requests to each other for pennies. (Basically text promises.)
The network effect in full effect.
So what's the advantage of Ripple? Well as far as I can see they don't have a USP.
And worse, even if a bank wants to start communicating with other banks using the Ripple network , each bank now has to create new agreements with each other. As opposed to Swift where you just sign up once.
Good luck with that.