The market for these kind of apps in Europe is very divided (just in the Nordics you have Swish, MobilePay and Vipps) but the dent in MC/Visas dominance is significant today. In 2 years, Klarna, Swish and Vipps will be more common both in e-commerce and POS that MC/Visa.

Do we need a pan-EU standard? I'm actually not so sure, but yes it would be nice when traveling.