This should be dead in the water but walmart customers have proven they do not care about anything more than saving a buck. If they incentivize its use, because they are saving so much from credit/debit transaction fees, I could see it taking off there. Just a fraction of their customers using it would give it mainstream status and other stores will start doing the same to compete.
Yes people educated about the flaws in the payment method see it as a terrible idea and not use it. People who will abandon their local stores, who offer their employees (neighbors) a livable wage, and drive 10 miles to a circus of terrible people, underpaid employees, and terrible customer service to save 5-10% have already sold their soul so this is just another benefit from the walmart to them.
I wouldn't care but I hate to see good ideas get shelved for bad ideas. Whoever can get the biggest userbase first is going to win ultimately and I can see walmart doing that easily.