Maybe one of your allies spares a couple million dollars he doesn't mind sending to you? Maybe you are in an urgent need of some cash or gold and your ally is ready to share? I find currency exchange and transfer necessary in this game, for some players own huge piles of money and are ready to give some of them away...
I am aware of the abuse that could result from such a feature, that's why some limitations might be added, like a sending limit in 24 hours, as well as a receiving limit, in addition to disabling the feature for any member below the a certain level, 20 for instance.
I'd really like to see this feature implemented in the game. I hope to hear from you soon.