While this is great (although very late) it's biggest issue is that I have to implement this and another service if I care about the other credit card companies. Merchants would be fools to just accept Visa.
FYI this isn't anything new. The networks (at least Visa and MC) have been routing payments to other networks for years, so that their customers don't need a separate integration with each network (or to use a middleman processor who has integrated with each network).
I don't see how it's different at all in this respect. If you want to support other payment systems or currencies, you need to implement Bitcoin and another service. Just like the GP was saying about Visa.
