If you're trying to discover new products of unknown quality and reputation, then it's not so good. For whatever reason, that seems to be the use case people focus on when criticizing Amazon on Hacker News, but I don't see how that can possibly be the dominant use case. Most of what people ever buy is not something brand new to them that they know nothing about.
I'm looking through my last several months of purchases here, and I'm seeing a bunch of automotive cleaning fluids, mostly from Adam's, polishing compounds and a respirator from 3M, a bunch of power tools from DeWalt, a Bose speaker. Known brands from reputable sellers, every item what I wanted and it got here quickly. In some cases, I either tried to or had to purchase elsewhere. For instance, Amazon had most of the DeWalt power tools I wanted, but was out of stock on rotary polishers, so I had to get it from some place called Acme Tools, and it took a week and a half. Amazon got me everything the next day. (I had a bunch of stuff stolen from my garage is why I needed all this at around the same time.) I tried to purchase the Bose speaker from Best Buy since I have one a five minute drive from me, and their website claimed it was in stock and I could pick it up the same day, but then right before the pick up window, they texted me to inform me they didn't actually have it and wouldn't for another week. So I canceled the order, went on Amazon, and they had free same day delivery.
It should be obvious that anything that goes from not existing 25 years ago to top five market cap company in the world is probably offering value somehow.