Yay GNU Taler is very promising, but I fear banks prefer proprietary systems.
It may become widely used if there's strong customer demand for GNU Taler, or regulation requiring an open electronic wallet. Most banks would probably be dragging their feet.
Imagine a future where Taler Systems SA becomes a financial powerhouse, holding a significant percentage of Euros to issue as tokens! Swiss bank accounts 2.0, giving Tether and USDC a run for their money.