Rather than a moat of details, it's first-mover advantage. Anyone can run a credit card network, but merchants and banks need to support them. Many others exist, but the issue is that they don't have widespread adoption. Solutions that work exist, which means the lesser supported alternative is not widely used, which again reduces reason for wider adoption...

Regulation changes "why bother" to "oh crap".

jup. once this is built, if adoption is lacking, it's not hard to imagine how the EU could make it the standard payment option.