> credit cards are giving you a revolving loan, there's risk it will not be repaid, and that risk ends up reflected in processing fees

Neither Visa nor MasterCard are loaning customers their money. It's the European banks that hold the bulk of the risk for European credit card transactions.

Also worth noting that who owns the risk is a regulatory question, not a technical or product one - and, like all regulatory questions, is different for different countries/regions.

Chip and pin and NFC transitions took off much quicker outside the US because merchants generally owned more of the chargeback risk than in the US, and therefore were willing to update their POS equipment accordingly.

Risk (like debt) is another place where a US-centric view will likely lead you to misunderstand the purpose of Visa/MC.