This makes me envious of you Americans. Here in Norway online shopping involves finding an online store that sells what you need (there's no site that sells everything, like Amazon, here), going through a cumbersome sign-up/payment process, paying a lot of money for the shipping costs, waiting several days and having to go to the post office unless the package is really small (or if you're willing to pay even more fo…
How often do you need laundry detergent? Every two weeks? If this button saves you ten seconds each time, that's a total of 4.3 minutes per year saved. And that assumes you buy the stuff one at a time instead of getting a bunch at once.
Amazon as a whole is great because you can use it for so much stuff. Saving time on a rare purchase is almost pointless, but saving time on all your rare purchases put together can be significant. But this button thingy is inherently single-product.
This is basically the ordering-side equivalent of when you buy three small items from Amazon and they get shipped to you in three separate gigantic boxes filled with vast amounts of padding. Maybe it makes sense when you see the big picture, but I can't help but scream "why??"