Actually you can only use your cards (travel or premium) to deposit to gambling sites. Withdrawal doesn’t work back to your card (you need your Iban - bank transfer -, but that’s only an option for people from the Nethetlands due to regulatory resteictions).
“Regardless of the card type used Mastercard , every deposit attempt will be identified using Merchant Category Code 7995, which applies to all internet gaming transactions.
Unfortunately, if your bank blocks this type of transactions, your card will not work.”
This is what I was told by PokerStars. So it is a restriction made by Bunq (even if their support not aware of this).