Gotta love that magical technobabble for things like that, (and was gonna guess that cause it is important for sake of ease of one currency instead of having boatloads of em.) Also totally a thing with the times even if it were like early fantasy-ish times cause the Knights Templar essentially invented the credit system. 

And noted for the things regarding the religions of the world.

Cool, yeah so I'll be working on a dude now.