You do not need to use the PayPal Cart buttons we offer merely to accept PayPal checkout payments. Our standard cart and buttons will offer buyers a PayPal checkout button in the cart. Unless you know you need to use PayPal's cart system for some specific reason, you would do best to use our standard cart and buttons.
Our standard cart presents a much nicer experience for buyers, as it appears to be part of your own site when the cart fades in as an overlay in front of your own pages rather than opening a popup window like PayPal's cart does. Our standard cart also allows you to use the Cart-based settings in your E-junkie Seller Admin (Shipping, Tax, Discounts), so you can manage all your product and cart settings conveniently from one unified place and only use PayPal to process actual payment funds.