i think it is most likely to be successful not as a consumer level product but at an infrastructure level. businesses will exploit the blockchain and end users will be using it without realising it, so moneygram and western union will use it to send money for you, you wont know, you will be sending euros, dollars, shekels, whatever but you benefit from lower transaction costs, say half of what WU currently charge but for WU they would be making more per transaction as a result of leveraging the blockchain and low cost bitcoin transactions.