Bitcoin itself is not a magic stick, it can't do nothing if people don't do actual work. I think that the answer to the question how bitcoin and blockchain can help poor countries lies into the governments of these poor countries. They can use the opportunity and create a business friendly environment for Bitcoin and blockchain related businesses by offering companies low to zero tax rates and a high quality personnel inside the country. I think that countries can spend money on educating their talented citizens about Bitcoin and blockchain technologies and make a very good developer out of them.
Creating the right business environment will attract more business to the country which will create more jobs and also increase government revenue through indirect taxes. There were reports that El Salvador have attracted more tourist as well as crypto related businesses since it made Bitcoin a legal tender. With more crypto awareness, young people will find different means to make money from the industry.