Oh, it's free internet money. If you are in crypto they keep you on side by giving you shitcoins every now and then which you have to sell fast before everyone realises they are worthless.
I've been struggling to define Airdrop to the many one person that has asked me recently. This should be in the dictionary :)
Its the only reason I can think that they keep doing em! Apart from getting money on the sly for themselves. Not any of our good Hive projects I might add :O)