Ronald All card payments are only accepted if they are fully supported by your account balance. It's definitely an incentive to not live from paycheck to paycheck if possible, but it's also the only way to ensure that you won't fall into debt through card usage (see also https://together.bunq.com/d/24396). Because a merchant can always decide to not give the deposit back to you, and there's no way for bunq or anyone else to see into the future and predict what happens.
That's also the whole reason for why car rental companies or hotels sometimes require these deposits. It's their security, because it's money that they can definitely get from you in case of damages or extra costs. Of course if you cause higher damages than the amount of the deposit, a company would still try to bill you for it, but let's say you would declare bankruptcy or just delay the payment a lot etc., there's not much that the company can do about it.
So yes, the bunq Mastercards are real credit cards, but everything (including deposits, 1 Euro/ 1 Cent verification payments, etc.) needs to be paid in advance. It gets refunded only after the merchant cancels the transaction or if the transaction expires automatically after some time.
