Bitcoin won't force them to start again; there are already (and will continue to be) ways to move your existing wealth into bitcoins.  However, bitcoins do level the playing field.  Corrupt third world governments will find it much harder to steal bitcoins from their citizens.  They will find it very hard to even know if they have any wealth.  The ability to earn, store and move wealth around would make a huge difference to the world's poorest.

I hear that mobile phone credits are used as a kind of pseudo-currency already in parts of Africa.  No one on this forum will need the danger of that explaining to them; but it's obvious that the people doing that are only one step away from bitcoins already.  Bitcoins facilitate trade, and trade is what will pull third world nations out of their poverty hole.