Most of all this airdrop are not worthy of the time spent on it, they are either worthless when received, a lot of them are after your private information, doing an airdrop of $15 in an exchange your personal info is highly risky, gone are the days of good airdrop in 2017, scam airdrop have taken over
And your personal information is much more important than the money you will get participating in it. Its just small amount of money and I don't thiNk you can earn enough money by joining in airdrop you can only get 5-15$ worth of tokens is this enough for the risk of giving your personal data to them which you don't know when they plan to use it after.