[pimeys]

I think the biggest reason is sovereignty: we cannot risk US cutting our payment system if they for example don't give Greenland for them.

I think this is the biggest reason to ensure you can pay with a local system in shops and restaurants.

[laurencerowe]

That's a very reasonable concern, though given how central Visa and Mastercard are I suspect it is probably necessary to regulate their structures within the EU so that intra-EU payments are not reliant on non-sovereign infrastructure.

[markvdb]

Regulating US companies operating in the EU still leaves a kill switch in untrusted hands. It doesn't solve issues like the https://en.wikipedia.org/wiki/Nicolas_Guillou problem.