On the Payment gateways page, your default payment gateways are Segpay first, then CCBill second. CCBill is turned OFF by default primarily because the fees are higher, but also because your site will likely launch with only approval from Segpay. CCBill takes a lot longer to approve sites so we often launch with only Segpay approval.
Once CCBill approves your site, you are free to display it as a default payment option, or leave it as a backup payment system. As a backup payment system, it will only be used when payments fail with Segpay.
Payment gateways can be turned on or off and reordered at any time.