[kevan]

>these prepaid cards are a very convenient lifeline to many people who would otherwise be shut out of the system.

On that subject, an interesting result of that lack of access is the existence of subprime retail, Bluestem Brands being a big example. Companies like this were able to coexist with Amazon because they're willing to extend credit to people who can't get a debit/credit card to pay at Amazon. The tradeoff is, of course, higher prices (~30% price difference compared to Amazon in many cases). The increasing prevalence of prepaid cards is definitely a net positive in my opinion. It's reducing an artificial inefficiency in the market and helping those on the most precarious rungs of the economic ladder.

Disclosure: I currently work with Amazon and used to work with Bluestem. I don't speak for either.