Bitcoin does pose a big issues for some countries, best example of these are Russia and China, where the financial system is not completely free and the local currency is controlled to an extent "we all know how much the US is trying to make China release it's coin to the world and hence improving in value, which would make Chinese products more expensive", Anyhow, BTC circumvent this since the local currency is traded to BTC "and mostly exchanged to USD earlier" hence impacting the price... Some countries ban it because it's hard to regulate and the countries are just incompetent.