Main things I can see are:
1. Low-cost remittances especially since most developing countries have plenty of overseas workers.
2. The unbanked. A recourse for people who does not/can not meet the requirements set by
traditional financial institutions.
3. An opportunity for individuals and small-scale business to transact/deal internationally without
having to go through banks/financial institutions.
I'm sure there are a lot more.
Offtopic:
I really find the term "third world" extremely offensive.
It is no longer the Cold War (half a century ago). Which was when terms like that were coined.
First World - U.S. , Western Europe, and their Allies
Second World - The Soviet Union, China, Cuba, and friends.
Third World - the remaining nations, which aligned with neither group and most were former
colonies
This 1-2-3 classification is now out of date, insulting and confusing. Who is to say which part of the world is "first"? And how can an affluent country like Saudi Arabia, neither Western nor communist, be part of the Third World? Plus, the Soviet Union doesn't even exist anymore.
http://www.npr.org/sections/goatsandsoda/2015/01/04/372684438/if-you-shouldnt-call-it-the-third-world-what-should-you-call-it