His method is not a troll or a scam,just an experiment for the bigger things like Running Ponzis.
->He conducts a giveaway to check if double spend methods are working on the provided addresses.
->He then starts a ponzi scheme ,sends couple of payments to show it's all legit to attract more noobs who have no idea those transactions will never be confirmed.
->Noobs wait for their 'doubled' bitcoins,forever.