Is there a meaningful difference between what the us has and what the eu has? Is everything 3% cheaper in the eu? What's the actual benefit consumers see
No, because in Europe sales tax is higher and included in the displayed price, so stuff is generally more expensive. But obviously everything is 3% cheaper than it would be if businesses still had to pay 3% fees. (credit card fees used to be really high before EU regulation came in -- the minimum fee was so high that merchants sometimes paid more in fees than they made in profit when a customer swiped a credit card instead of a debit card).
But the much bigger advantage is that reward cards aren't a thing, and credit card usage is much less common. Most people just use their debit cards. Credit card debt is much less of a problem because credit cards aren't advertised like they are in the US. People spend less if they don't always have $3000 of credit available.