Originally Posted by **********

There are lots of reasons.

You can use your own merchant account but it means getting one set up with a bank. Your own bank may not want to process for adult for example. Your bank takes on risks processing for you which means you have to have good credit, good processing history, etc.

Using a 3rd party company has benefits. They are usually easier to set up and approval is easier too. 3rd party companies combine both merchant processing, a payment gateway, and user management. Some 3rd party processors offer built-in affiliate programs and a multitude of billing options that may not be normally available to you. They also offer billing and technical support to your customers which smaller companies may not be able to take on.

The best thing to do is to contact the ones you like and ask each of them all of the questions you can think of, then decide which one(s) are best for you and your business.