Half the price, not sure, but for me the main appeal is I can find the things in the first place. If you need something specific, it's just impossible to find it in the city. There are 10 places that may have it, you go there, nobody knows where what is.
If there was a search engine for brick and mortar I might be inclined to buy there again. But I just can't find anything.
But then I can't find the thing I want. Amazon seems to be doing their level best to make searching a pain in the ass, but it's still leagues ahead of using Maps to hunt down the type of store that may have an item, then going to the website of the store (if they even have one), then looking for the item if they have a shopping/product-list section on their website, then hoping it's even accurate and I don't drive out there just to find they don't actually have the item.
So instead I go on Amazon and deal with scrolling through pages of not-the-thing-I-actually-want and hopefully find the item available for delivery sometime in the next 1-5 days.