I think it's better to invest in a project that has an interesting and potential concept, because nowadays a lot of airdrops that are scams only waste our time, it's better to invest in bitcoin and other big 10 altcoins
Even do investing is not easy to do and have risk it is still worth than getting free coin because mostly free coins are not worth it and waste of our time. Invest to a potential project or choose wisely an investment to avoid scam project. But its up to you if your going to invest or participate in Airdrop to get free token, like what I said above all decision is all yours just make sure everything is alright before you do it.