FTC orders Mastercard to open debit transactions to competing payment networks
engadget.com
engadget.com
The point is I believe, the payment can be settled outside of the mastercard network, but mastercard only allows their service to perform the mapping between token and PAN, and force settlement to happen over the mastercard network. The idea here is that the token can be taken by another card network, mapped to the real PAN, and then settlement happens between the issuing bank and merchant over the other network.
I.e. instead of acquirer <-> mastercard <-> issuer it becomes acquirer <-> X-Network <-> issuer, even though Mastercard was used to create the initial link between device and bank account.
I don't think many people even understand why pin numbers are required for debit instead of the 'free' credit options.
We know how that went last time. I wonder if the process has been fixed, or if it will be gamed again.