Bitcoin as a form of earning has supported most users from third world countries to fulfil their daily needs as well to grow bigger with better living standards.
I assume you are talking about people earning Bitcoins with signature campaigns? If so, then it's a great thing that it can help them in their daily lives, but what if at some point these signature campaigns are not allowed anymore? It's not a likely scenario, but what if? How will people without any useful skills earn coins? Earning around $1-$2 per day farming faucets and captcha sites for the entire day?
In my view, country that adopts bitcoin will easily get out of their poor economic situation in a very short time.
Impossible. Every year there is (supposedly) billions of dollar in form of donations going to countries in need of help, but in all the years nothing has happened. In fact, things have become worse. Put that against a few individuals making $10-$20 per week, how on earth will this get an entire country out of its misery? If the incentive for improvement isn't coming from the governments there, then it will never happen.