Why, in Japan, do i see cars with pink rims?

I am living out here in Japan. Occasionally I see a Scion xB (Toyota bB out here) or some other Japanese car with pink or purple painted wheels. I want to know the style behind painting rims those colors. I'm not much for chrome wheels, so i would normally go for black wheels, because it really looks better to me but would it be more JDM-style to paint my rims pink/purple? I was thinking of buying some 18" wheels (currently on 17's). The 18's would be black and the wheels i have now would be pink or purple. just wondering if anyone has any knowledge on the matter. and please, if you own a mustang or charger, you probably don't know and i'm sure your opinion won't count. thanks.