Airdrops are useful only to those who organize them, because they give little, and they ask that he do a lot of activities.
What ''a lot of activities'' ? You just have to fill your eth adress / email in 99,9% of cases. It's not bounty campaigns where you need to work your a** off
Well you put your information and you do follow up from time to time if you received your airdrop tokens. It's time, isn't it? Even if little time, are you happy with what you get from airdrops? I'm not. So I prefere not to spend this time for airdrops personally.