I'm gonna be a bit more optimistic, the ratio of scam is clearly unbelievable, I would say 95% for my experience. But this is still a way to put a finger in crypto and I don't think we should put it down too much.
It can bring people to project that don't have big funds for marketing, it clearly make people understand the way crypto work also, I mean just to handle your eth adress, you gonna have to go to my etherwallet, try to understand what is an erc20 (alien language at first) and lot of other stuff.
If you sale at the good time (LOL) you can on a year make between 500 and 2000 dollars I would say, lots of airdrops can reach the 20/30 dollars, some exceptional one will go more than 500, few anyway but that's not their point. I do airdrop and bounties on regular basis, not every day but almost, take max an hour a day instead of watching garbage on TV for most people, and it makes you go through so many crypto project (even Ripple made an airdrop long time ago in another galaxy).