I think the bounty thread is very helpful to the project team, but the air drop is not very helpful to the project team.
Most of the time, air drops only attract people to sell tokens, and even negative publicity for the team.
I also believe that Bounty campaign is very useful for the project. It attracts many people and potential investors. Airdrop - also attracts people, but often spoils the reputation of the project, so I think that airdrop has a bad effect on the project.