Bounties are still worth the effort as long as you happen to find a legit bounty, meaning not scam and the rewards has value and tradable.
While airdops are free but only few projects are real because most of them are just scam.
If you have a plenty of time to join in bounties and airdrops then why not? Its free anyway but dont expect too much.
The worth of it depends on the project that you join in.