The participation in the airdrop does not take a lot of time. You get free tokens for a little time of work. I think it is good. The most important is to choose the right project for airdrop to earn more money.
You are right airdrop does not take a lot of time and many people participate in the product. Airdrop is good to attract community but it is also necessary to create such product that people will use for a long time and it will be necessary for people.
That is why it is very important to check the project before participating in the airdrop to evaluate the potential of the project and value of the tokens.