Why should I give my bank account details for a payment ?

Electronic funds transfer (EFT) is nothing but direct money transfers between two bank accounts. Even though EFT is the fastest growing payment method worldwide and the most common in many countries, it may be new to some users.

Here are some reasons why you should consider using EFT:

• Low costs
  EFT is the most cost efficient payment method for merchants. "OK, why should I care ? The costs are on the merchant anyway." you might say. But that's not all true. Merchants calculate their prices by costs. Check or credit card payments are costly. If a merchant can save on these costs, he is most likely to offer his products cheaper.

• Wide acceptance
  Almost everyone has a bank account - not everyone has a credit card.
  

• Security
  While credit card fraud is the number one reason the internet is viewed as insecure, there is no such thing like EFT fraud. Anyone could abuse your credit card details for fraudulent web purchases. This will not be possible with EFT, because there are much stricter identification requirements. (By the way: you are giving away your full bank account details everytime you write a check.)
  EFT transactions are protected by strict banking laws. In case of doubt, any transaction may be disputed by an accountholder.

• Disbursements / No checks
  Since it is only possible to send money to a credit card as a refund to a prior charge, EFT is the only alternative to checks for receiving money. And just like writing checks, also receiving them is a more or less troublesome task.

Need more info ? here are some independent links:

USA:
www.nacha.org
www.directdeposit.org