A very good article @lennartbedrage. It is original content. This has been so scarce, unfortunately. Thank you.
I am sorry I am too late for giving a useful up-vote, but I am not too late for following.

I have a question about Ripple that would affect you analysis, if you don't mind:

How does the Ripple system use XRP? I mean that if a bank wants to use the Ripple network to transfer money, does it have to exchange their fiat money to XRP? Or does have to pay a transaction fee only?

I am sure you can appreciate the difference. If the bank has to pay fees only, then the size of GDP is not important, and hence, the analysis is not correct.