i think bitcoin can't help poor country because in poor country. alot of them have a currency not easy to bitcoin help them
If there is an easy way of exchanging the local currency to bitcoin and vice versa then I think the picture might be different.
However I believe that bitcoin can help the economy of a person and not the entire country. Changing the economy of a country is a very tough job and it requires huge input for some individual bitcoin group, and I doubt anyone would try to do that in real life.
Exchanges will be on every country in the world, some of them just need time and the necessity of it, you don't will open an exchange where there's no people using bitcoin...
Bitcoin it's something global and this can help poor countries, they can earn more per hour than working in an local store, of course, they need experience to do some online work.