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Europe’s $24 Trillion Breakup With Visa and Mastercard Has Begun
(europeanbusinessmagazine.com)
This is a most excellent place for technology news and articles.
It doesn't require an app. When you pay, you select your bank and it will redirect you to a page that the bank provides. My bank provides a QR-code I can scan with their banking app, but it also offers a log in form to pay.
So I guess it is based on what your bank is willing to provide.
This is based on my experience with 'iDeal' the predecessor of wero.