I am a "savvy shopper" and have no desire to buy components on Amazon anymore. Their stock co-mingling doesn't work for speciality computer components. I've received items marked as new that were clearly open box returns. I've received completely nonfunctional components. I've received the wrong item a few times. The component I've had the most success with are SSDs, but for anything beyond that I prefer to buy from brick and mortar because of their "curation." To be honest, it's a shame because the Amazon shopping experience is vastly superior but they send you crap, so it's unusable for this vertical. I still buy other junk from Amazon, but nothing that's particularly performance sensitive.
If the customer isn't savvy the knowledgeable customer service adds a lot of value.