Is it? Assuming nobody opposed you, you'd need to convince merchants to have a different payment terminal and train staff on it. You'd need to convince POS providers to provide an integration. You'd need to convince banks to allow your card to be accessible in their systems (or find an alternative way for your customers to pay their card). Once this is done you have to convince people to become your customers for a card that only works in some scenarios.

Assuming absolutely everyone felt neutral about this, what's the incentive for any of the above parties to say yes? For everyone involved it seems to be a lot of work for little benefit.

When they block a payment it’s typically due to some interest group threatening bad PR hit pieces on them.

If you’re running a duopoly money printer, the worst thing that can happen is to have people realizing it and talking about it.

Hence why you’ll never hear an ad from Mastercard or Visa touting the dominance of their payment networks or even trying to sell you their products. It’s always brand-washing PR fluff about saving whales or Olympic ice skaters.