The ability to ean money on airdrops attracts a lot attention to it.
The more popular and in demand the project the more people want to participate in the airdrops.
It is a good opportunity to get for free tokens of new and prospective projects which price will grow in the future.
Every day a lot of new projects appear but it is difficult to predict how successful will be a project in future.
Participation in airdrop allows to get tokens of the projects for free for promotion of the project.