Given a travel related situation, and given a specific question about the situation, summarize the question into a title
Q: While traveling in the EU, with both a Visa and Mastercard issued in another country within the EU, does it have disadvantages if both the cards are debit cards?

Would one need a credit card for the sole purpose a debit card is not accepted but a credit card would be?

If ordering products online from a EU country, are there possibilities of credit cards being accepted and debit cards not?

A:
When traveling in the EU, are there significant differences between paying with credit or debit cards?