I am pessimistic the existence of bitcoin can help poor countries, if it makes the person or group might be able to. No countries which only depend on one sector of the economy, let alone the bitcoin.
Who told you that these countries will solely depend upon Bitcoin? Bitcoin earnings will be supplementary. Bitcoin can help poor people to cut down their expenses. For example, Western Union and Moneygram charge as much as 15% for remittance payments to certain countries. Usage of Bitcoin can bring this down to less than 5%.