Totally agree -- this platform looks very cool -- the deposit approach is pretty elegant.
The deposit approach *is* elegant but there is a bootstrapping issue with it. If the fiat currency holder has only fiat currency and *no* bitcoins then he can't put up the bitcoin deposit to start the Coinffeine-based exchange which he wants to carry out in order to get bitcoins. :-(
I agree. If you are going to an exchange to purchase bitcoins and have no bitcoins yourself. How do you put up the deposit?