If you use USD and want Yen you don't necessarily have to exchange them. You can start working for Yen. It's the same with bitcoins. You don't have to buy them you can just start services to earn them. I like it better because then you don't have to give out your ID to some online company!
I got your point. Bitcoin is usually based on the price of dollars so for other country or developing country like japan or others it may hard for them to buy bitcoin on their currency because the value on it to dollars is way to small or not equal in terms of price on bitcoin. So risking a lot of money may be a hard thing for some. So I recommend to have a source of income though signature campaign where you can earn bitcoin without using your own money. For me its better to work hard while earning to learn more.