You missed an important point: if they wait until checkout then the payment process will complete and they'll get to walk away with law enforcement's money.
They have every incentive to wait until the very end to tip their hand.
They have every incentive to wait until the very end to tip their hand.
For all we know this screen upon checkout is random, and whoever doesn't complain to get their money back is the cop. Most fraud outfits have major customers they deal with or cashout teams they offer specific BINs over chat, the online store is for bottom tier thieves on public sites.