I don't buy the Asia or Africa argument, for the near seeable future at least, people in Asia and Africa that can afford 1st world prices have access to credit cards. Because these relatively poor 3rd world masses (by western standards), these newer 3rd world Internet users, can afford a WAP, smartphone, or tablet does not automatically make them porn paysite, camsite, or dating site paid in buyers. I hope in the next 10 or 20 years their economies will prosper and at that point they will have more disposable income.
The internal mainstream ecommerce (within the national borders and currency) may be more able to utilize digital currencies but with a much, much lower unit value as 10 bitcoins might be 3 years income to these people you are suggesting to target. These target people are not hi-tech geeks or rocket scientists -- they are newcomers to the digital age with simplistic needs.
They have already learned how to fap for free on the Internet anyway -- they don't have a lot of disposable income.
