She probably is the god for only one particular nation, and nothing else.The in-universe lore recognizes the presence of a god and yet the first to receive god's chosen one is the state.
It worked for peaceful Japan. Other than that, the while the god seems powerful, she isn't omnipotent (visits barrister once and says she has to go because she's busy raising a group of heroes). She's probably more the type to delegate than deal everything by herself.What's more, the god claims that the world doesn't do well due to the strife the world has so then what's the point of implementing the law when mere mortals preside as judge?
They are in a transition period and there are currently no better figures to serve as the judge. It would be politically troublesome if the king appointed anyone especially a noble as a judge.Even worse, the authority figure is revealed to be in an unstable position so what worth does he have?
It seems weird too but it looks like weeaboo god indeed - they seem to have been using yen as a currency for years considering that the general shop girl had a contract worth 10M yen four years ago. It's safe to assume that Japanese systems have been implemented for much longer, and it was only recently that the god found a Japanese lawyer who was free.I hate how everyone in that kingdom is so well versed in japans laws despite it being like what, a damn month since it was implemented?