Since 2009 as we know satoshi nakamoto create Bitcoin and it entire ecosystem, some of advantages of cryptocurrency are transparency, decentralization and help people making transaction worldwide with low fees. Many of international NGO that work in poor country are earning money for themself where they are asking money to help these country and keep some of these fund for them, we remember the scandal of Red cross after the recent earthquake in Haiti in 2010 where they build one house for some million of dollars.
Blockchain can help for transparency about how donation are making in the world and be sure that fund go to concerned people, i think that UN used Ethereum Blockchain to send fund for 10 00 Syrians Refugees. And UNDP and Electrichain and thesunexchange launch a solar project in Moldavia.
So for about transparency i think that the blockchain bring a lot of thing for people in poor country.
And about a problem that can be solved by the Blockchain is that about election because especially in my country people are always and dont trust election result because they can give their own result, but is the election can be run on the blockchain and we all can know the vote of each, and this problem can be solved.