It’s the delivery. I can often get something inconsequential for net cheaper, faster from Amazon. Local stock is usually next day. And I can often get stuff internationally cheaper and faster through Amazon than the real retailer.
The delivery part of the service is really good when things go right.
Very difficult to get a hold of someone when they lose a package even when they explicitly tell you “contact us”.
But if you stick to inconsequential items, it’s great. I needed a few USBC cables and charging cables the other day and got them next day at half the price. I checked the local stores and none had what I was after.
I have gotten a fake product one time (public domain book, PoD instead of what I wanted and what apparently used to be under that URL) refunded, no questions asked, even got to keep the book (anyone in Germany interested in an HP Lovecraft decent quality hardcover PoD book?).
I realize that it’s apparently way worse in the US, but there supposedly are issues here as well, I just never encountered them (or the products are so well-faked that it’s a distinction without a difference).
Fast delivery, a lot of choices, both "Aliexpress but faster delivery for a price", but also EU products, and a customer service that does pretty much anything asked.
You’d have to duplicate this to take them on.