In this case, opt-in is playing double meaning. But you're right, in order to work, a significant number of people and business must opt-in and treat it like a

In this case, opt-in is playing double meaning. But you're right, in order to work, a significant number of people and business must opt-in and treat it like a currency to be spent. I don't think that's a prohibitive problem inherently, though obviously still a tough one.