When you choose to pay the TurboTax product fees out of the Federal refund, there is a 39.99 service fee for that payment option (44.99 for California filers.)
That permits an intermediary third-party company to open a temporary bank account in your name to receive your funds from the IRS. After setting up your account, their bank receives the funds, subtracts the fees, then sends the rest on to your bank (or card.) The intermediary bank then closes the temporary bank account it set up for you.