I find that interesting because Amazon is a "no impulse buy zone" for me. Everything I buy there is meticulously planned. It is probably an effect of living in Hawaiʻi - shipping can kill a good deal very quickly (and Amazon, while I'm at it, you know where I live - stop telling me that the item is free to ship when it isn't!).
I'm working in Antarctica and everything takes at minimum 3-4 weeks to arrive (often 6) after ordering, so it's really taken the starch out of impulse buys.
Amazon doesn't deliver most physical things to my (current) home, so all of my purchases are Kindle (impulse) buys. I'm guessing that for a lot of international readers the Kindle Store is the most important part of Amazon.
An reason I used to use to stop that behavior in myself was "oh, it will take a few days to get here". It's difficult to use that logic these days. If one day Amazon could get it to me in an hour without extra fees I'm in trouble.
It's too bad they haven't expanded faster - Walmart just barely rolled out their curb side pickup service where I live - if Amazon had made it here with same day delivery even just a few months ago we'd be customers for life, but as it is we'll probably stick with Walmart for groceries even when Amazon does eventually get here. (better the devil you know, etc.)
I'm sure if you totaled up my Amazon purchases and my Steam library it's cost me thousands.