Low effort for a possible high reward. It is worth it and if the project is good the airdrop should be fun and will boost your initial investment. If you just a bounty hunter that dumps and doesn't care about projects well that's just sad.
Nowadays many ICOs offer free coins, but we have two problems with this free coins, the first one the value of this coins will drop after start trading due to a lot have free coins willing to sell it, and the second they ask for your ID (KYC), and i think it is very risky to send your IDs to any one.Please vote to help others
If you prefer to working easy without much efforts, airdrop is the most suitable for you.
Another cryptocurrency activities such as trading, bounty hunting, or investing will consume your power and time.
But the profit you can generate in airdrop will be much lower than other activities.
If you have nothing else to do it is worth your time. it depends, you have to decide for yourself if it is worth it or not. Also, many people give up with too much ease. You can get a decent small income with faucets even if you work with referrals and have good seo and advertising skills.