[Qualman]

Amazon has an established reputation as a low-priced retailer, and stakes its reputation on that. Twitter seems to intend this as more of an ease-of-purchase kind of feature. My expectation is that there is little to no incentive for Twitter to be pricing these products competitively.

[pradn]

Not everyone comparison shops for all products. Many people are happy paying a standard price for certain goods, without hesitation. For example, expecting to pay $10-15 for a t-shirt is common, as is paying $1 for a song. For these sorts of purchases, reducing the friction from discovery to purchase is pretty important. Suffice to say, I probably wont buy a car or a vacuum cleaner on Twitter.