Reinforcement from an unlikely quarter!
The Big Ugly for anyone working in retail the past 20 years is that stores have done almost nothing to improve workers' productivity. Price scanners were a 1990s innovation and there hasn't been much to follow. So it's very hard for workers to make an economic case that they should be getting paid more. (There's a human-decency case, but that doesn't always prevail.)
In fact, average retail wages were 62% of the national average pay in 2000, and they're 55% now. More numbers are here: https://www.forbes.com/sites/georgeanders/2017/05/23/the-loo.... What was a bad job then has become a worse job now.
Wal-Mart's new initiative isn't entirely beautiful, but it represents the first effort in a long time to say: "Hey, we discovered something about you that's more valuable than we realized. Your commute home is a potential asset to us, and to date we've paid you zero for it. We've now got a mechanism to pay you something for it, as long as you're willing to do Task X for Payment Y."
It's a lot easier for wages to go up -- in any field -- when workers create more value. We can argue about whether Wal-Mart has defined Task X and Payment Y properly, but at least this is a fresh idea in a field that's been devoid of them for a long time.