Why does Warlight only accept PayPal and Credit Cards?

Because rolling cash up and shoving it into the USB port doesn't work very well.

I don't mean that..............................................

I mean why can you not use payment methods like gift cards.

Can't you just use the gift card (assuming we're talking about a general gift card, like Visa's) as a credit card? Usually credit means "credit, but also maybe debit and/or gift (if they work)."

What kind of gift card are you talking about? Most places only mainly accept credit anyway, and you can link PayPal to other things (like your bank account) if you want to pay using those.