There may be other options to accept payment for an add-on, other than PayPal or Stripe. I guess you could accept payment with electronic currency, . . . bit coin. As far as needing a bank account, unless you have that, you can't transfer money out of PayPal. But, you don't really need to transfer money out because you can use PayPal to buy stuff directly, or transfer money to other people. Although, you can't buy anything on Amazon directly from your PayPal account. I don't remember if you can set up a Stripe account without a bank account, it might be possible with PayPal. Depending upon the area of the world you are in, there may be other payment services available. I did have a situation where someone from Mexico had their payment rejected, I guess because my payment system wasn't set up to receive international payments.
For the very few paying customers I've had, the vast majority of them will use PayPal instead of Stripe.