I also ignore airdrop nowadays. I used to be active in participating airdrops back 2015 - 2017 because airdrops during those years really worth a lot. Developers are generous airdroping a Bitcoin worth of their token and there is no need to follow, retweet etc conditions. We just need to drop our wallet address and voila, we are airdropped with their coins that is on the exchange for trading.
When 2018 come lots of scam project saturate the market, others even refuse to pay or send the promised airdrop so starting that year, I often ignore airdrop messages and invitation to participate.