Those are owned by the major banks, European banks, sure, but still private. Payment systems like these operate like private tax collection, levying a regressive tax on all transactions which flow through them. That’s from transaction fees which exceed the cost of processing said transaction.

I would much rather have a state-owned payment processor, which operates at cost, or is even completely funded by taxes. The extra tax revenue that would generate from increased economic activity would far outweigh its cost.