Airdrops were worth* a try when cryptocurrencies weren't widely known, and they were their way of promoting the project. Nowadays, there are more professional promotion methods, so airdrops are no longer profitable or worth exploring.
* Before 2017
I absolutely disagreed with you mate. Airdrop's still worthy to try. The problem is that it's evolving so fast. It went from doing free task to the actively participated by using the real money.
I'm still actively participating in the airdrop. I get 1k bucks recently just from staking retroactive (XPL). I get even 5x ROI from participating in the pre-sale by ZKC for its prover participants.
It's still worthy exploring as long as we have money cuz it's not free anymore. There may be some that's offering free task to get token, but always ended with the dust.