I worked at Etsy when it expired and the execs got this question a lot. The TL;DR is that the expected outcome is that it massively increases the support burden (wait I didn't mean to click that; wait I actually need to send it to another address; wait I didn't realize shipping was a hundred dollars) without really enabling more sales. So it was a neat idea and worth trying when ecommerce was new, but now we know enough about ecommerce to know that the user has to confirm details of their purchase.