The popularity of bitcoin is not too high, its limited to a certain extent so we cannot consider it as a international currency at a moment.
True, bitcoin is still unknown in different countries, need to start PR it, i don't know how cause it's still and also illegal in some countries. Hard situation.
Most developing countries are new to innovation and with that to bitcoin. Which is not really bad. just remember paypal is also new in many countries. To build a reputation you need time.
Time bitcoin is getting so there is no problem. Just be patient.