A bank or any lender wants interest on loans because that is what keeps them in business. If they did not have interest they would not make any money and in hand would not be able to pay people to keep there bank going. The difference between direct deposit and a check is that direct deposit is a wire transfer from one financial institution to another. This means you would be able to withdrawl the full amount of the check the day it is deposited because the wire is like cash. If you cash a check it usually takes 3 to 5 days for the check to clear.