The buttons had a "dedupe" setting to allow only a single pending item until said item was delivered fwiw.
I really liked the dash buttons for two reasons:
1. It made ordering something you regularly and only buy online anyway easy for an entire household, like for my use case, hookah coals roughly every month.
2. You could place the button next to where you store said consumable and most folks would prefer using it over asking for a link or reminding someone else to re-order.
I do think it was a mistake to launch with an initial limited set of branded buttons for common household goods most people pickup at the store anyway (like detergent) instead of a generic button for my point 1's usecase but thats just plain-old BigTech thinking.
Re 2: I always got a chuckle seeing that "slim jims" were one of the buttons and could envision someone getting into their pantry only to notice they are down to their last 2 slim jims, but thankfully they have a dash button right there to avoid this future disaster.
I never got one, but they certainly made sense in my mind for something like laundry detergent, etc. You notice you are getting low, hit the button, forget about it and 3 days later it shows up and you go "oh, right perfect".
I mean I think the point is that most people want to price check before they just buy something, even if it is the same item on repeat.
Given later advances in smartphones, I think I'd rather have a little QR code or NFC sticker that encodes "saved product 123".
Then a platform-agnostic open-source app on your phone pulls up the matching entry (e.g. "toilet paper" or whatever) and gives you a fast way to go to the previously-ordered products' page.
Then you aren't bound to any particular vendor, you see prices before ordering, and you could use the same system for other kinds of locationally-bound notes or tasks.