I foresee a future in which the "EC card" (please let's call it Girocard, because that's it's name) ceases to exist in a few years.
Banks are already in the process of issuing Visa or MasterCard debit cards to customers as top-of-wallet product, and issuing girocards only on request, sometimes also with additional fees. Visa/MC debit cards have much easier integration with Apple and Google Pay. And they can be used online, and are easier to be used internationally, as they are accepted in most places where Visa/MC credit cards are accepted, too.
The recent deprecation of the Maestro card scheme by MasterCard, which has been co-badged on virtually every Girocard for many years and which allowed the cards to be used during international trips in most countries, has only resulted in aforementioned moves of banks away from the Girocard to be accelerated.
If the EPI does not quickly come up with a card scheme that is a) very very cheap for merchants and b) rolled out quickly in all of Europe, the debit card market in Germany will fall into the hands of Visa and MasterCard. That's just how it is, unfortunately.
The bad joke behind all of this is that this entire outcome has essentially been kick-started by the European Union moving to cap interchange fees on Visa/MC debit and credit transactions - a move against Visa and MC, but one that backfired and opened the doors for national card schemes to essentially be eaten alive by those very two actors. That's because that move made these transactions cheap enough for many big merchants to start accepting these cards in the first place. Before the cap, those rates were outrageously expensive, and virtually nobody outside of the travel business accepted them.