Its a marketing tactic mate, the developers give the free coins under the name of airdrop and make a strong community in less time.
Airdrop is giving free tokens with some rules with the aim of wanting to get the support of a large community quickly and instantly. for now if we want to get a reliable airship it is very difficult but we can meet the running project path or get a linsting token to be listed in the exchange
They just using people to have a free advertisement thus helping them to have a token circulation in the market. Airdrops before are literally a free money but today it's literally a shit.
You guys shouldn't waste time and effort joining those scam airdrops and besides that will just cost some bucks, if you're lucky enough but if not, those tokens will be just a token of appreciation.