The organizers of the project do not care about your time. They try to collect the largest amount of money in the shortest possible time. And so they use all the tools to attract the community. Don't listen.
What makes sense is what you say. Therefore, it is better for you to participate in a bounty program than to be airdrop. Because airdrop is certainly easy to do but the value is higher for bounty. As said that the project did not really deal with the time you spent participating in or working on airdrop.