Lets agree to disagree here. Im still not convinced that ALL crypto is legal payment, if this would be the case, than the public articles about that topic would state this too, and not only mention BTC. But maybe I will find a japanese friend that can confirm what you told me.
But your point is indeed true, Mona got a huge upside potential, BTC suffers in regard to transaction cost and speed, about NEM I cant say much. Do you know how many transactions Mona can handle per second?