Credit cards & banking are much less distributed outside the developed world. While in the US, 63% of the 15+ population has a credit card, in Mexico it's barely 13% (in Latin America in general it's only 18%). This is a HUGE obstacle for e-commerce and bitcoin's cash-like, informality (no requisites, no need to register or be approved by a central entity) might allow it to spread where banks have so far been unable to. (Source World Bank Financial Inclusion Data http://datatopics.worldbank.org/financialinclusion/)