Nothing. Square further propagates the status quo (plastic cards). There's no disruption involved. That's why Visa is an investor.
If they become the new merchant-interface, there's nothing stopping them from offering an alternate payment mechanism that doesn't rely on credit or debit cards.
Another is that Visa believes that Square is a threat, thinks they may be successful and has invested to mitigate that threat, get visibility into their activities, and so on.
No. I was replying to this...
Starbucks already has wifi. Don't most payment processors use some sort of Internet connection these days?
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