I think this refers to the part where they select "Purchase of goods or services" instead of "Cash advance". This way, Amazon will eat the fee as a way to promote use of the service. They want you to use it for actual trade between different entities (e.g., accept it on your web site)--not to fund your new company (I guess you may do that, though, if you select cash advance)

Disclaimer: IANAL, TINLA