[hocuspocus]

The EEA cap on fees only applies to interchange in 4-party schemes, i.e. the part that goes back to the issuing bank. PSPs typically charge between 0.7 and 1.5%. But yes, it's possible to do much better than countries like the US. For starters because card-present fraud is virtually nonexistent, and online fraud is drastically lower thanks to SCA.

That said, you're right, there's a fundamental difference between moving funds in an immutable way (whose marginal price tends to zero) and a payment system.