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 from yobit is not airdrop because as far i know people can claim it as much as they want and the amount of free coin were totally worthless even it cannot be traded on yobit because too low and in this case if you compare to airdrop rewards i think from airdrop program you can get pretty much higher than collect free coin from yobit