Wero is not widely supported yet, it's not even finished yet, it doesn't have feature parity with existing solutions. Compared to its predecessor, Giropay, it's also rather intransparent, in a "just trust our app, bro" kind of way, with little in the way of open standards.

It needs support from every single bank to work (in stark contrast to PayPal, btw), and that support requires quite a lot of development and maintenance effort on the part of the bank. Parent poster (BarHocker) said many European banks already support it, but the practical reality is most of them don't, and largely didn't have any plans to, either. The number of supporting banks is artificially inflated by the fact that the German Volksbanken/Raiffeisenbanken and the Sparkassen, respectively are technically hundreds of small regional banks.

This requirement to have direct support from the individual banks is, the way I see it, the main reason why Giropay failed. If Wero has the exact same problem, I don't see why it would succeed where Giropay did not.

I do still hope for it, though.

I'm afraid you're wrong. We've had something very similar to Wero in Sweden since 2012 - it's called Swish. It helps, but it unfortunately doesn't get rid of the need for visa and mastercard.

Wero has a specific functionality. He is not talking necessarily about consumer-facing systems here. For european banks there are other systems and infrastructure that need to be thought about.