[notahacker]

The fact that even millions of people who earn a BTC transaction fee per week have access to dumbphones is rather irrelevant to the observation that cultures who are resistant to banking are likely to continue to value gold jewellery over exotic computer-based financial instruments that don't look good around their neck. And that's even assuming a hypothetical world where many developing world citizens actually have practical access to BTC and local markets for exchanging BTC for goods.