How is amazon going to undercut my barber or the brewery I go to with this data? It seems like there are plenty of businesses that could benefit from this and not be at risk to the "empire".
This isn't an Evil Plot, it's just an attempt to leverage their existing payment processing abilities to get themselves a piece of Square's pi, much in the same way that AWS leveraged their existing IT infrastructure.
Could they mistreat retailers who are trying to make a living reselling boxed products? Yeah. But those retailers have mostly been killed off already by Big Box stores. This ship sailed long ago.
Hair cutting drone perhaps?