Airdrop on the other side is the simplest and easiest way of distribution, it's free and don't need too much task to get some and it is in favor of the recipient at the first glance but it would somewhat helps the dev or his project to have a large community of supporters and advertisers as well, yes it's FREE but it's a way of distribution, how would you get your coin into the market if you're the only one having all of them?