Do you think they're only using this for groceries and that it will never be expanded to other retail? In the article it says they are already in talks with other vendors. This means your hand does more than just buy groceries, it will work anywhere there is a palm scanning terminal. It will work at WalMart or Best Buy to buy thousands of dollars of electronics, or maybe even one day to buy a car. Maybe your phone will even be able to read palm prints, and you can buy and sell private goods, or illegal goods using it. That's a lot more than a bunch of groceries.

If people are willing to go to these extents then the biometrics aspect is just a red herring.

They kidnap your spouse/child/parent and threaten to murder them unless you go through with the transaction. They hold a gun to your head while you transfer the contents of your bitcoin wallet to them. They beat you with a rubber hose until you give them your safe combination.

Maybe you're right. This may make people safer, because they no longer need to threaten your life to get your PIN. They just knock you out and cut off your hand. At least you are still alive that way.

Sure but if you're walking into a store you can use my contactless card. Using my hand is kind of...unnecessary.

At that point, you're just cutting off my hand for the sake of it.

I think the idea is that Amazon is big enough to make palm prints a strong precedent that eventually ends up in things like expensive cars.

An employer of mine used biometrics (palm scan) to control entry. They dropped it and went back to NFC cards and PIN. Never explained why.