Regardless if it is a credit card or a debit card. This way of purchase is still connected with additional expenditure for many in europe. Including the risk of financial data exposure. Many are not ok to give direct access to critical data when there is an easier and saver method like paypal.
i don't say Paypal is the ultima ratio - there is nothing like 100% safety and there will never be - but maybe there is a possibilty to use a similiar service instead. Personally I will not purchase anything as long as there is no alternative to the current purchasing methods. Simply because it is connected with expenses that exceed a tolerable degree - and there is a good chance that i'm not alone. Really bad for me, as i am a great fan of Pathfinder. Worse that the local assortment is less than desirable and often badly translated. Probably bad for Paizo too as there might be a great amount of missed sales