A lot of depends from the project. Now gaming NFT projects attract a lot of attention and their airdrops are very popular. Just see the results of this airdrop
https://twitter.com/spacegrime/status/1396545308809601025 and you can see how popular gaming airdrops and how many users they have.
Now there is a big variety of different NFT in games and it attracts a lot of gamers to the cryptocurrency industry. Also appeared a lot of NFT marketplaces where it is possible to create and sell NFT. Airdrop is a good opportunity to attract money to NFT.
It is very important to have a good liquidity for NFT marketplace and also for game with NFT. To increase the liquidity airdrops are very popular.