add support for European debit cards, i.e. Maestro
Currently Stripe and Paypal are available as payment providers but for European countries they only support credit cards.
Unlike other areas in the world (E.g. USA), in Europe the majority of card payments are done via debit cards supporting the Maestro system, not credit cards. It's not uncommon that people don't even have a credit card.
Example of payment provider that suports EU debit cards: Ingenico (ogone)