We're not quite there yet with seamless international transfers. I live in the UK, if somebody sends me £1,000 in BTC I need to change this into fiat money. Right now the only way I can do this is by registering on an exchange, providing all my ID + verification (sound familiar?), then listing the BTC for sale. I suspect the same is true in most countries. So Western Union still has a place until such time that BTC can be converted to and from fiat effortlessly OR there are 1000s of retailers accepting BTC as a valid form of payment. I'm really hoping for the latter!