It depends on the kind of debit card apparently. What I have is a girocard[1], which doesn't have the required 16 digit card number and CVC. I didn't even know that debit cards can have those. My online payments are usually made via SEPA bank transfers, Giropay[2] or Paypal.
[1] https://en.wikipedia.org/wiki/Girocard
[2] https://stripe.com/docs/payments/giropay