Well, it's called airdrop for a reason. There are always different ways the token creator can look into for the distribution of tokens. The more unique it is, the higher possibility of them creating a hype or even starting the trend for a particular method.
Take telegram bots for example, it was a well thought method and it has become a popular trend now.
Airdrops is one of the ways on distributing coins which i do agree that it do somehow contribute on making such hype or awareness of coins existence.There are lots of distributions actually and the good thing here is that you can really earn those coins for free without the need on pulling out money from your savings or on your funds. Regarding on airdrops there is an specific board where those airdrops been announced which you can actually find it here
https://bitcointalk.org/index.php?board=238.0