Still now centralize exchanges have a good trading volumes and a lot of traders. Listing on big exchange is a good promotion to the project.
It is very difficult to pay attention to the project without promotion. How do you plan to promote the project?
Now they have airdrop. You can check information about it in twitter. I think that airdrop is a good way for promotion and to attract attention of users to the platform.
Now many projects prefer to use airdrop because in airdrop it is necessary to pay users in tokens of the project.