I'm still wondering why developers will organize airdrops and distribute an amount of tokens which is far lesser than the minimum amount of the tokens that can be deposited on an exchange for trading. If you don't want the users to cash out the money, why do you let them waste their time?
Well to gain attention to the investors as part of their marketing strategy, because they'll think that there will be free money for them and thinking that the dropped tokens were like a little "short" for them so they'll invest even more. For bounty hunters, it will be simply because they know that they'll join the campaign to promote their project through social media. They're not just gaining investors, but they're also gaining people to promote the project.