why I believe SPT will succeed, page-9

Here is my question.. why can't Mastercard/Visa do this themselves?

With APT - the answer is kind of that the payment ideology involves credit risk. Mastercard and Visa already engage in credit risk so for them it would need to be an entire different arm of the company etc.

With SPT - they have no credit risk because MC/Visa and the retailer hold the risk. So MC/Visa could implement holds on their own cards with this system and have no additional risk to their current products? I'm guessing it's the retailer network that makes this valuable, i.e. if MC/Visa wanted to do this, they would need a team working to onboard retailers who want to do this?