I see a lot of airdrops running here and there.
Why would people launch them? They pay gas for creating a contract and then pay gas to transfer tokens for free. So I guess there must be a reason and a hope for a return on these investments.
Many projects are trying to accumulate huge user base through those airdrops.
It's cheap for them (sending tokens with 2 gas in 1-2c) and they are getting the user attention by this.