I dont think you can make a lot of money on airdrop. But if you have enough free time and there is no other source of income, then you can try. In any case, it does not require much time and effort.
Free coin in yobit is like a faucet that you play. You can click the button to earn rewards. You should wait for an hour to get another reward, but some coins can be claimed in less than one hour. No, you still need to have the effort always to click the button to earn rewards, and that will depend on how long you can stay in that site to claim the rewards.