it should also be noted that if you are buying something very expensive with bitcoin you can make the transaction offline and it will be instantaneous. You can do this with paper wallets/physical bitcoins. So like if you are going to buy a car you dont have to wait an hour at the dealership. You just load up a barrier bond with the full amount of the car before you leave the house. When you get there if you were able to talk the salesman down than you would negotiate to have those bitcoins refunded as a rebate. The car salesman would simply look up the public key in the blockchain and make sure it had 6 confirmations and then forward the funds to his own wallet.