Traditional methods of exchanging value such as credit cards and bank accounts rely on an idea of an account at a financial institution.

In order to make a transaction with with a bank account or credit card, the sender must send the account information to the party they want to
send the money to, either in the form of a credit card number or as a bank account. (Paypal is an exception, although you do have to give paypal your credit card numbers and/or bank account numbers)

Because you're transmitting these account numbers to another party, there is a risk that they either get intercepted or that the other party uses them or sends them to another party.

Because these account numbers (along with some additional information) can unlock funds transfer, there is a risk of fraud from stolen account information.

Credit Card Numbers are stolen (statistics)

Bank account numbers

When performing a Bitcoin Transaction, no information that can be used to steal bitcoins is released. The senders Bitcoin Address, which is revealed in the bitcoin transaction, is not useful for making any further transactions, nor is the receiver's Bitcoin address.