It turns out the shortsighted legislature forgot to make it illegal to sell wine from a vending machine: "as long as the user is asked to take a breathalyzer test, swipe their state issued ID or Driver License, and then show their mug to a state official sitting somewhere in Harrisburg, who is keeping an eye on the proceedings via CCTV." I'm surprised nobody thought of this sooner.
The system was developed by the Pennsylvania Liquor Control Board, who runs the "State Store" system. The machines are run by the LCB. This isn't some magic end-around the law, it was developed by the exact people the legislature has designated to decide how to sell wine in the state.
Also, Wal-Mart is not the first to have the machines. There has been one in my local grocery store (Giant Eagle) outside of Pittsburgh, PA for a while now. They've also had single bottles and 6-packs of beer available for even longer. (Beer sales are generally limited to "distributors" who can only sell full cases, or bars/restaurants/delis who can sell single bottles or 6-packs. Giant Eagle sells ready-to-eat food in that part of the store, so they were able to get a deli-style license for beer sales.)
The wine vending machines are stupid. The selection is very limited, and the machines only operate during the same hours that the state-run Liquor/Wine stores are open anyway. Given that I have to drive past a state Liquor store to get to the store with the wine vending machine, it's pointless. I just make the extra stop.
The beer section is decent, but single bottles/6-packs are overpriced. I just go to a beer store and buy a case.
At least all of this is a step in the right direction. Maybe someday they will actually allow grocery stores to really sell alcohol like other states. I'm not holding my breath, though.