Does anyone knows and uses an alternative?
Not yet but hopefully in the next months: https://wero-wallet.eu/
Curve right now. Granted you have to Register yourself with a Credit Card from them, but then you can add your existing ones onto the App and instruct Android to use that App instead of Pay.
I read their Privacy Policy. They share a lot of Data with other companys. I know for that this is needed to transfer the money, but they also share data with advertising companys. I think Wero would be better in that point
Many European banks have their own contactless payment solutions. Here are some examples (it’s a German article): https://www.kuketz-blog.de/nfc-datenschutzfreundlich-bezahlen-mit-dem-android-phone/
They usually also work on (not European, but Canadian) GrapheneOS with no issues.
For what purpose? And what country/region?
For paying in supermarkets or shops
If you need contactless or card payments in a shop; use your card.
Unless the shop supports a scheme through an app or other service. That depends on the shop and the region.
