In context of doing business in this industry, background profile stays at, uhm, the background. What matters, at least to me, is the performance and to a lesser degree, the looks.
Which is why I think if someone comes from JP or KR, such association earns them extra bucks, even if they're not as good as advertised. But maybe because we wanted to prove to ourselves that after watching too much JAV, we want to go further and check out JP HGs. It is something that's discriminatory to Thais, Mongolians or Vietnamese who not only perform their job well, but also have nice attitude but can't (or hesitate to) charge because their peers don't charge that high.
In short, I don't care if you're from Timbuktu or Tahiti, if I like your style, it's nobody else's business.