Wouldn't it be kind of difficult to enter exact amounts with only 2 buttons? Not difficult I mean tedious...
You don't need to enter any amount on this thing, you enter it on the PC.
OK, say you want to make a transaction. You fill out four things in the PC client: the wallet to transfer from, the amount of BTC, the destination address and the password for the wallet.
You press OK, and the transaction is sent to the device via USB for signing. On the device you see the amount, wallet and destination, and you press the OK button. The device sends the signed transaction back to the PC, and the PC client publishes the transaction on the 'net.
So you need a client on your PC to communicate with it, i.e send the ammount? Isn't this then just basically keeping your wallet on a USB drive?
I'm confused.