Bitcoin is as virtual as the credit cards and online banking networks people use everyday. Bitcoin can be used to pay online and in physical stores just like any other form of money. Bitcoins can also be exchanged in physical form such as the Casascius coins, but paying with a mobile phone usually remains more convenient. Bitcoin balances are stored in a large distributed network, and they cannot be fraudulently altered by anybody. In other words, Bitcoin users have exclusive control over their funds and bitcoins cannot vanish just because they are virtual.
