There are two main reasons why you may want to buy Bitcoin using an American Bank Account instead of debit/credit cards or e-wallets like PayPal. First, the cost of using a bank to invest in this digital coin is far much lower than that of a credit card. Second, a bank transfer is the only method you can use to buy large amounts of this coin. Credit cards have low limits, depending on the issuer. For example, American Express users can’t purchase more than $1,000 worth of BTC monthly.